S) and long (tRNase ZL) forms. Based on the sequence characteristics, they can be divided into two major types: bacterial-type tRNase ZS and eukaryotic-type tRNase ZL, and one minor type, Thermotoga maritima (TM)-type tRNase ZS. The number of tRNase Zs is highly variable, with the largest number being identified experimentally in the flowering plant Arabidopsis thaliana. It is unknown whether multiple tRNase Zs found in A. thaliana is common to the plant kingdom. Also unknown is the extent of sequence and structural conservation among tRNase Zs from the plant kingdom.tRNase Z removes the 3'-trailer sequences from precursor tRNAs, which is an essential step preceding the addition of the CCA sequence. tRNase Z exists in the short , which prevents tRNase Z cleavage of mature tRNAs. Examination of flowering plant chloroplast tRNA genes reveals that many of these genes encode partial CCA sequences. Based on our results and previous studies, we predict that the plant TM-type tRNase ZSs may not recognize the CCA sequence as an anti-determinant.We report the identification and analysis of candidate tRNase Zs in 27 fully sequenced genomes of green plants, the great majority of which are flowering plants. It appears that green plants contain multiple distinct tRNase Zs predicted to reside in different subcellular compartments. Furthermore, while the bacterial-type tRNase ZSs and hint at the possibility that these proteins may have been selected for their ability to process chloroplast pre-tRNAs with whole or partial CCA sequences. Our results also support the coevolution of tRNase Zs and tRNA 3'-trailer sequences in plants.Our findings substantially expand the current repertoire of the TM-type tRNase Z In pSaccharomyces cerevisiae and fission yeast Schizosaccharomyces pombe, the endonucleolytic cleavage of nuclear pre-tRNAs requires the presence of the yeast La protein  and tRNase ZL (700-800 aa), which are encoded by different genes. It is believed that the tRNase ZL gene has evolved from a tandem duplication of the tRNase ZS gene, followed by divergence of the sequence  of tRNase Zs [tRNase Z is distinguished from other MBL members by their unique substrate binding domain termed the flexible arm . Based on flexible arm type, there are two major types  and one minor type [RNase Zs . The bacRNase Zs . The eukT. maritima and A. thaliana [The TM-type tRNase Z was believed to be the minor type at the time of discovery since it was found only in thaliana . The flethaliana . In addithaliana ,40,41. Tthaliana ,33, wherthaliana ,29,40.ELAC2 delays cell cycle progression, suggesting that ELAC2 may be involved in cell cycle control either directly or indirectly via its role as tRNA processing enzyme [β represent a monophyletic group of land plants and green algae that evolved near the base of the tree of eukaryotic life. Flowering plants (angiosperms), which are typically polyploidy, represent the largest, most diverse and most evolutionary advanced phylum of land plants making up 90% of the plant kingdom. It can be divided into two major groups: dicotyledons (dicots), which accounts for the majority of the angiosperm species, and monocotyledons (moncots). At present, there are at least 27 sequenced and annotated genomes representing the major taxonomic groups within green plants, although the majority of them are those of flowering plants. The public availability of these genome sequences enabled us to identify tRNase Zs in green plants and to study their evolution.In this study, we undertook a comprehensive survey of candidate tRNase Zs from annotated green plant genomes. To understand the evolutionary relationships among green plant tRNase Zs, we further conducted a phylogenetic analysis of these newly identified candidates. Finally, we presented a detailed sequence analysis of tRNase Zs with the intent of further delineating the distinct features of green plant tRNase Zs.Mimulus guttatus) MguTRZ2 (Phytozome accession no. mgv1a024577 m.g) in the database was incomplete lacking the N-terminal region. We were able to predict this region from the genomic DNA sequence based on sequence similarity. The predicted full-length coding region of MguTRZ2 has 364 aa. As another example, the sequence annotated as the candidate castor bean (Ricinus communis) tRNase ZL (Phytozome accession no. 30146.t000117) appears to be mispredicted due to the presence of sequence gaps. Thus, this sequence was excluded from the list.To extend our previous study of tRNase Z diversity and evolution, we searched public genome databases for putative green plant tRNase Zs with significant matches to known bacterial and eukaryotic tRNase Zs. Since most of candidate sequences identified from the databases are computationally generated without subsequent manual annotation, it is likely that many predictions may contain errors. Therefore, we verified each candidate. We first validated each prediction by reciprocal searches against the GenBank. In back-searches, a candidate was confirmed if reverse BLAST also gave tRNase Z hits in the top matches. Accuracy of prediction was further evaluated by multiple sequence alignment. All discordant candidate sequences were checked manually for possible errors including sequencing errors, intron mispredictions and existence of gaps in the genome sequences. We found that many candidate sequences are apparently incomplete or contain annotation errors. For example, the predicted coding sequence of the monkeyflower (Ls from flowering plants including papaya (Carica papaya CpaTRZ3), cassava (Manihot esculenta MesTRZ4), Medicago (Medicago truncatula MtrTRZ3) and black cottonwood (Populus trichocarpa PtrTRZ3). After re-evaluation of intron splice sites using FGENESH_GC, we were able to recover their HEAT motifs. Because the intron sequences of some candidate sequences appear to be extremely difficult to predict correctly, we could not conclusively rule out the possibility of errors in certain candidates.Several incorrect predictions are apparently caused by the presence of the non-canonic GC-AG splice site pairs. While the GT donor splice site is a canonical 5'-splice site for introns in eukaryotic genes, the GC donor splice sites account for the majority of the non-canonical donor splice site. Thus, for those that cannot be accurately predicted by the conventional FGENESH program, we carried out gene prediction using FGENESH _GC, which is a new version of the FGENESH program including noncanonical GC dinucleotide in donor splice sites. Indeed, by doing so, we could predict some exons encoding missing conserved motifs. For example, the HEAT motif was originally missing in several annotated candidate tRNase ZS and 32 candidate tRNase ZL were identified from 27 green plant species including 21 flowering plants, 1 moss, 1 lycophyte and 4 green algae  and four green algae  allows for evaluation of differences between flowering plant tRNase Zs and those from basal land plants and green algae.In total, 54 candidate tRNase Znclature . Of thescterized . While mSetaria italica) contains the largest number of tRNase Zs (5) so far identified in a flowering plant. Most flowering plant species have a single tRNase ZL. In contrast, six flowering plants including two Arabidopsis species  harbor two tRNase ZLs. It should be noted that the presence of two tRNase ZLs are not species-specific since the plant species containing two tRNase ZLs come from diverse taxonomic groups.The flowering plants examined to date appear to contain multiple tRNase Zs. Foxtail millet  and foxtail millet have three tRNase ZSs and four tRNase ZSs, respectively. The presence of multiple tRNase ZSs appears not to be grass-specific, since three other grass plants including rice (Oryza sativa), Brachypodium (Brachypodium distachyon) and maize (Zea mays) contain only two tRNase ZSs. Calculation of the percentage identity and similarity between candidate tRNase Zs from these two grass species shows strong conservation of the proteins at the amino acid level with the most identity (93%) and similarity (95%) between S. bicolor SbiTRZ2 and S. italica SitTRZ2 .Unlike most flowering plants that possess two tRNase Zdentity 9% and simP. patens, which contains two TM-type and one bacterial-type tRNase ZSs, and one tRNase ZL. In contrast, two green algae C. reinhardtii and V. carteria have the least number of tRNase Zs, comprising one TM-type tRNase ZS and one tRNase ZL. The two other green algae M. pusilla and O. lucimarinus contain one TM-type and one bacterial-type tRNase ZSs and one tRNase ZL. The lycophyte S. moellendorffii, which has the smallest genome size of any land plant reported, contains two tRNase ZLs in addition to one TM-type tRNase ZS.The number and type of tRNase Zs appear to be highly variable in the two primitive plant species and four green algae Table . The larS. moellendorffii tRNase Z-like protein (SmoTLP2) appears to lack all of the conserved motifs.Interestingly, tRNase Z-like proteins (TLP) which apparently lack one or more conserved motifs of tRNase Zs necessary for the enzymatic activity of the protein are widespread in basal land plant and green algal genomes that have been analyzed here Table . Many tRS-like and tRNase ZL-like proteins which are comparable in size to tRNase ZSs and tRNase ZLs, respectively. The number and form of tRNase Z-like proteins vary among the species, being largest in C. reinhardtii (two tRNase ZS-like and two tRNase ZL-like proteins) and next largest in S. moellendorffii (two tRNase ZS-like and one tRNase ZL-like proteins). The basal land plant P. patens and the two green algae M. pusilla and O. lucimarinus contain one tRNase ZL-like protein, whereas the green alga V. carteria contains one tRNase ZS-like and one tRNase ZL-like proteins. In contrast, black cottonwood (P. trichocarpa) appears to be the only species among the flowering plant genomes examined that contains the tRNase ZL-like protein. This species contains one tRNase ZL-like protein in which the second His in the His motif is mutated to Gln (data not shown).Based on their sizes, tRNase Z-like proteins can be divided into tRNase Zin silico the subcellular localization of each of flowering plant tRNase Zs using different bioinformatic prediction programs. Most flowering plants have two tRNase ZSs (tRNase ZS1 and tRNase ZS2). All tRNase ZS1 proteins apparently lack any predictable signal sequences and therefore predicted to be cytoplasmic proteins, with the exception of O. sativa tRNase ZS1 (OsaTRZ1), which is predicted to be localized in the chloroplasts (Table S2 except P. trichocarpa tRNase ZS2 (PtrTRZ2), contain a predicted chloroplast targeting signal  carrying multiple tRNase ZSs, only one tRNase ZS (tRNase ZS2) from each species is predicted to be chloroplast-localized, whereas the rest are predicted to be cytoplasmic  or two (tRNase ZL1 and tRNase ZL2) tRNase ZLs. Most tRNase ZL1 proteins contain a predicted mitochondrial targeting signal between two putative translational initiation sites at the N-terminus and also have a nuclear localization signal  [A. thaliana tRNase ZL1 (AthTRZ3) was found in both the nucleus and the mitochondria [A. thaliana tRNase ZL2 (AthTRZ4) predicted to have both nuclear and mitochondrial targeting signals is actually found only in the mitochondria [Besides tRNase Zal Table . Some tR0-80 aa) . Consistze-range -80 aa [Aze-range -80 aa [AS from T. maritima as outgroup. Phylogenetic analysis reveals the presences of two well-supported clades: one formed by including all TM-type tRNase ZSs, and the other all tRNase ZLs and bacterial-type tRNase ZSs  from the two Arabidopsis species  together form a group sister to a group formed by another two tRNase ZLs (AlyTRZ3 and AthTRZ3) from the same two species. Likewise, the two tRNase ZLs found in some species including Aquilegia coerulea (AcoTRZ3 and AcoTRZ4), Glycine max (GmaTRZ3 and GmaTRZ4) and S. moellendorffii (SmoTRZ2 and SmoTRZ3) are sister to each other with a posterior probability value of 1. These observations suggest that tRNase ZL gene duplication took place in certain species.To gain insights into the evolutionary relationship among plant tRNase Zs, we reconstructed the phylogeny of 86 candidate sequences using Bayesian phylogenetics. Although most of plant species are flowering plants, they are taxonomically diverse. In addition to tRNase Zs from plants, we also include tRNase Zs Figure . The latSs are analyzed first. A list of aligned tRNase ZSs from representative green plants is shown in Figures Ss from T. maritima, B. subtilis, E. coli, the cyanobacterium Synechocystis sp. PCC 6803 and humans are included as needed. A full list of all aligned green plant tRNase ZSs is presented in Additional file To assess the presence and conservation of motifs in candidate green plant tRNase Zs, we performed multiple sequence alignments of identified tRNase Zs sequences. Candidate tRNase ZSs from the flowering plants appear to be more similar to each other than to either the basal land plants or green algae  and tRNase ZS2 (AthTRZ2) exhibit only 17% - 24% and 16% - 21% identity (25% - 35% and 27% - 31% similarity), respectively, with those from T. maritima, B. subtilis, E. coli and humans. Overall, the sequence conservation between the green plant tRNase ZSs and non-plant species is largely confined to the highly conserved motifs of tRNase Zs.Sequence comparison reveals that except for the N-terminal regions, tRNase Ze Figure . FurtherSs reveals that most of the proteins possess several unique features that distinguish them from bacterial-type tRNase ZSs and thus justify their classification as TM-type tRNase ZS. The sequence logos for motifs unique to TM-type tRNase ZSs are presented in Figure Ss harbor the TM type flexible arm. The plant TM-type flexible arms show only weak protein sequence homology to the bacterial-type flexible arms, and have distinctive features including the absence of the GP motif and the presence of a consensus sequence KLKxxYxxLxGxxIxxLK, here termed the KL motif  and green algae reveals that in addition to the well conserved Motifs I-V, these candidates possess a bacterial-type flexible arm containing the GP, HEAT and HST motifs, and the variant PxKxRN motif, in which Lys is replaced with Leu , which seems to be a driving force in plant evolution and variation [Unlike ariation . HoweverSs, which are clearly distinct from the bacterial-type tRNase ZS, represent the TM-type tRNase ZS. A comparison of motifs found in three different types of tRNase Zs from green plants is provided in Figure Ss in green plants  in the cytoplasm [In contrast to the TM-type tRNase Zytoplasm .Ss (tRNase ZS1 and tRNase ZS2) are predicted to be either in the cytosol or in the chloroplast, whereas one of tRNase ZL (tRNase ZL1) is predicted to contain both nuclear and mitochondrial targeting signals. The second tRNase ZL (tRNase ZL2) found in some plants either contains or lacks a predicted mitochondrial targeting signal. These predictions are generally supported by recent subcellular localization studies of A. thaliana tRNase Zs [A. thaliana tRNase ZS1 (AthTRZ1) and tRNase ZS2 (AthTRZ2) are localized in the cytoplasm and chloroplast, respectively, whereas A. thaliana tRNase ZL1 (AthTRZ3) and tRNase ZL2 (AthTRZ4) are targeted to both the nucleus and mitochondria, and the mitochondria, respectively [It is likely that multiple tRNase Zs found in the flowering plants are localized in different subcellular compartments. In most of the flowering plants examined, the two TM-type tRNase ZRNase Zs . A. thalectively .S2 and tRNase ZL1 are involved in the 3'-ends processing of pre-tRNAs in the chloroplasts, and both the nucleus and mitochondria, respectively, whereas tRNase ZL2 either serves as a back-up for mitochondrial pre-tRNA 3'-end processing or plays a specialized, yet to be discovered function. The function of tRNase ZS1 is unknown. It may play a role in repair of incorrectly processed 3'-ends of tRNAs in the cytosol. Alternatively, tRNase ZS1 could also participate in nuclear pre-tRNA 3'-end processing, as suggested by the observation that deletion of both A. thaliana tRNase ZS1 (AthTRZ1) and tRNase ZL1 (AthTRZ3) results in a lethal phenotype [Based on their predicted subcellular localization, it is most likely that tRNase Zhenotype .T. maritima tRNase ZS cleaves after the CCA sequence which is encoded by all but one tRNA gene, leaving the CCA sequence intact [A. thaliana tRNase ZS can process pre-tRNAs with the 3'-terminal CCA sequences embedded in the trailer sequence, albeit at a different position [74 regardless of the sequence of the flanking region [The CCA triplet following the discriminator generally inhibits tRNase Z activity, with the first C at nucleotide position 74 having the greatest effect ,33,58. Te intact . Similarposition . Like thg region . Importag region .A. thaliana tRNase ZS appears to be unusual in that it can also cleave off the 3'-terminal CCA sequence from mature tRNAs in vitro [S in vivo, it is likely that the plant chloroplast protein may acquire the ability to recognize the 3'-terminal CCA sequence as the mature tRNA 3'-end via cofactors [However, in vitro . Since mofactors .T. maritima and plant tRNase ZSs lack the GP motif but contain the KL motif. Additionally, they are significantly smaller in length relative to those of other tRNase Zs possessing the anti-determinant function. Structural studies reveal that although TM- and bacterial-types of flexible arms share a similar overall structure which is composed of a compact globular domain and an extended two-stranded stalk and protrudes from the protein core, they have different globular domains [α-helix, one long helix and one 310-helix, whereas in the bacterial-type flexible arm, it is composed of two α-helices, two β-strands and one 310-helix. It would be interesting to know how the differences in the sequence feature, length and topology of the flexible arm may contribute to cleavage specificity by the enzymes.The mechanisms responsible for cleavage site selection and CCA inhibition are not fully understood, but appear to involve a combination of sequence features. First, the flexible arm has been suggested to contribute to cleavage site selection and the inhibitory effect of the CCA sequence . This tR domains -28,64. IT. maritima tRNase ZS has suggested that the Ser31 and Thr33 residues of Motif I are involved in the cleavage site selection, with the former residue being more critical [T. maritima tRNase ZS affects the cleavage site selection [Another possible motif involved in selection of the cleavage site has been suggested to be Motif I which appears to participate in binding the acceptor stem of pre-tRNA substrates ,62. In vcritical . HoweverT. maritima and A. thaliana [Ss found in all flowering plants examined so far also lack this motif  has been identified. This protein does not exhibit any tRNase Z activity in vitro, consistent with the lack of some of the most conserved motifs of tRNase Zs in the protein sequence [tRNase ZPCC 6803  and fungPCC 6803 , whereassequence . Since cL has arisen from the fusion of duplicated tRNase ZS genes with further sequence diversification. It is possible that tRNase ZS-like proteins found in the basal land plants and green algae may represent relics of original tRNase ZS that were mutated during diversification of eukaryotic tRNase Z genes. Alternatively, these proteins may play species-specific functions as suggested for cyanobacterial tRNase ZS-like proteins [S genes may occur early in green plant evolution.It has been suggested that tRNase Zproteins . The preLs and two tRNase ZSs. One tRNase ZL is predicted to participate in 3'-end processing of nuclear and mitochondrial pre-tRNA, whereas the other is likely to provide a backup for mitochondrial pre-tRNA processing. It appears that most tRNase ZSs, which is widespread throughout the green plants, belong to a minor but highly distinct type of tRNase ZS (TM-type). In contrast, the typical bacterial-type tRNase ZS is restricted to basal land plants and green algae. The apparent lack of the bacterial-type tRNase ZS in flowering plants suggest that while both types were present in the basal land plants, the bacterial-type tRNase ZS was discarded in favor of TM-type during plant evolution. Based on our results and previous studies, we propose that like T. maritima tRNase ZS, TM-type tRNase ZSs found in green plants seem not to recognize the CCA sequence as an anti-determinant and that the rise of this type of tRNase ZS appears to accommodate the 3'-end processing of chloroplast pre-tRNAs with partial or whole CCA sequences. This unusual property of green plant tRNase ZSs is likely due to multiple sequence determinants including the TM-type-specific flexible arm comprising the KL motif, Motif I and lack of the PxKxRN motif.This study represents the first large-scale identification and analysis of green plant tRNase Zs. Our survey of current plant genome databases shows that green plants are represented by multiple tRNase Zs, which include one or two tRNase ZSs. The complete understanding of the mechanisms of the cleavage specificities of the TM-type tRNase ZSs awaits the determination of the structures of these enzymes bound to pre-tRNA and the accumulation of more precise biochemical data.However, it should be noted that bioinformatics analysis alone cannot resolve possible differences in cleavage specificity among TM-type tRNase Zhttp://www.phytozome.net/, the NCBI nonredundant protein sequence database http://blast.ncbi.nlm.nih.gov/Blast.cgi, Joint Genome Institute  as an outgroup as described [7 generations, and every 1000 generations were sampled. The burn-in parameter was estimated by plotting -lnL against the generation number using Tracer 1.4.1 http://beast.bio.ed.ac.uk/Tracer, and the retained trees were used to estimate the consensus tree and the Bayesian posterior probabilities.Phylogenetic analysis was performed using the Bayesian approach, with escribed . Brieflyescribed . After eescribed  to choosescribed  using a S: the short form of tRNase Z; tRNase ZL: the long form of tRNase Z; β-CASP: MBL-associated CISF Artemis SNM1/PSO2; CPSF-73: the cleavage and polyadenylation specificity factor; MBL: the metallo-β-lactamase superfamily; TGF-β: transforming growth factor-β; TM: T. maritima.pre-tRNAs: tRNA precursors; miRNA: microRNAs; tRNase Z: tRNA 3' endonuclease; tRNase ZThe authors declare that they have no competing interests.LF, ZW and JL performed online database searches and sequence analysis. JY carried out a phylogenetic analysis. YH conceived this study, analyzed the data and drafted the manuscript. All authors have read and approved the final version of the manuscript.Distribution of candidate tRNase Zs identified in green plants. Abbreviations for species names are indicated in the parentheses. +The number of amino acids in plant tRNase Z and tRNase Z-like proteins. *Indicates that mispredicted sequences obtained from the databases have been corrected. ?Indicates the sequence could not be correctly predicted.Click here for fileS. bicolor and S. italica tRNase ZSsPairwise sequence comparisons of . The accession numbers for proteins are listed in Additional file Ss from S. bicolor and S. italica were calculated using the Clustal W program [ program .Click here for fileSs from S. bicolor and S. italicAlignment of candidate tRNase Z. The accession numbers for the candidates are listed in Additional file Click here for fileSs identified in green plantsAlignment of candidate TM-type tRNase Z. The accession numbers for the candidates are listed in Additional file Click here for fileLs identified in green plantsAlignment of candidate tRNase Z. The accession numbers for the candidates are listed in Additional file Click here for file


Background. Macrosomia is defined as an infant's birth weight of more than 4000 g at term which is to different maternal and neonatal complications. Several studies have been done on factors influencing risk of macrosomia, but there is lack of information and study in our country regarding macrosomia complications. Objective. The aim of this study was to determine the prevalence of macrosomia and its complications. Method. A cohort study was conducted from 2007 to 2011 at Obstetrics and Gynecology Department, Razi Hospital in Ahvaz city, Iran. All pregnant mothers who were referred to Obstetrics and Gynecology Department for delivery were included in this study. The total number of 201,102 pregnant mothers was recruited and divided into case and control groups after delivery (macrosomia (case) and normal weight infants (control) groups). Results. Out of total deliveries , there were 1800 macrosomia, (9%). Gestational diabetes, maternal obesity (BMI), maternal aged and positive history of previous macrosomia were the major risk factors for macrosomia which were compared with the normal weight infant groups . Neonatal complications associated with macrosomia included humerus—clavicle fractures and arm—brachial plexus injury which were significant compared to the control group . Conclusion. The macrosomia is potentially dangerous for the mother and the neonate. It is important to recognize the suspected fetal macrosomia to prevent its risk factors and complications. There is a need to provide all delivery facilities and care services to prevent and reduce the maternal and neonatal macrosomia complications. Macrosomia is described as a newborn with an excessive birth weight. Fetal macrosomia has been defined in several different ways, including birth weight of 4000–4500 g  or greater than 90% for gestational age after correcting for neonatal sex and ethnicity (90th percentile) [Morbidity and mortality associated with macrosomia can be divided into maternal, fetal, and neonatal categories. A study investigating the effects of birth weight on fetal mortality shows that higher fetal mortality rates are associated with a birth weight of greater than 4250 g in nondiabetic mothers and a birth weight of 4000 g in diabetic mothers . MaternaMaternal weight prior to pregnancy or obesity can affect the weight of the fetus. Women who are obese are more likely to have larger infants . ExcessiMacrosomia neonates are at risk for shoulder dystocia and birth trauma. This risk is directly related to neonatal birth weight and begins to increase substantially when birth weight exceeds 4500 g and particularly when it exceeds 5000 g. Brachial plexus injury is rare, with an incidence of fewer than 2 cases per 1000 vaginal deliveries. This risk is approximately 20 times higher when the birth weight is more than 4500 g . StillbiRace and ethnicity are associated with macrosomia. Macrosomia occurs with higher frequency in newborns of Hispanic origin. Because Hispanic women have a higher incidence of diabetes during pregnancy, part of the preponderance of macrosomia in this ethnic group is due to the higher incidence of diabetes in pregnancy. However, even when corrected for diabetes, Hispanic mothers tend to have larger newborns.Fetal sex influences macrosomia potential. Male infants weigh more than female infants at any gestational age. Recent studies have confirmed this association . ExcessiA cohort study was conducted at Obstetrics and Gynecology Department, Razi Medical and Educational Center, Ahvaz, Iran, during the years 2007–2011. The study was approved by the Jundishapur University of Medical Sciences and Ethics Committee.There were about 20,000 live births during 5 years. They were divided into two groups  and normal birth weight (control) groups). The inclusion criteria were those with singleton pregnancy regardless to maternal age, number of parity, type of previous delivery, and agreement to participate. The exclusion criteria were incomplete subjects' profiles. The subjects were matched with respect to personal characteristics. We obtained the written informed consent form from the research subject.The outcomes measurements were maternal characteristics and medical history , delivery details ), nutritional status , and maternal and perinatal morbidity data. χ2) test with considering odds ratio (OR) was performed. Fisher's exact test was performed for variables with frequency less than 5 in each cell of 2 × 2 table. Data was analyzed using SPSS, version 16. The entire test was 2 sided significant at the level of 0.05 by estimating power of 95%. Normality test was performed, and all variables were normally distributed. The chi-square (n = 240) had birth weights between 4500 to 4999 g. Only 0.2% had birth weight about 5000 gr or more  infants had birth weight of about 4000 g and above. A number of 1520 (7.6%) infants had birth weight between 4000 to 4499 gr and 1.2% ( or more .P < 0.05). The results showed that 712 (39.5%) of diabetes subjects delivered macrosomia neonates. Also there was significant association between maternal obesity and macrosomic infants (P < 0.05). Maternal obesity was a risk factor for macrosomia. Out of 1637 obese pregnant mothers, 1350 (75%) delivered macrosomic neonates. a significant association between multiparity and macrosomia (P < 0.05) was observed. About 81% (n = 1458) of macrosomic neonates were delivered from multiparity mothers. There was a significant association between positive history of previous macrosomia and postterm delivery  (n = 162) delivered macrosomic neonates (Sixty percent (60%) of mothers and having macrosomic infants-aged 35 years and above. About fifty-nine (59.5%) of subjects and having macrosomic infants were of Arab ethnicity. There was significant association between macrosomia and diabetes (ameters) . The resneonates . This inn = 211), cervix and vaginal laceration (n = 92), and uterine rapture (n = 10). There were significant associations between macrosomia and uterine atony, cervix/vaginal laceration and uterine rapture  (n = 37), and a clavicle fracture (n = 14). There was a significant association between macrosomia and brachial plexus injury and clavicle fracture . About 180 macrosomic infants had first-minute Apgar score of less than 6 which was significant compared to normal birth weight infants (P < 0.05). Brachial fracture was observed in 6 macrosomic infants that were significant with normal birth weight neonates (P < 0.05). Shoulder dystocia was observed among 192 neonates that 11% (n = 183) were macrosomia fetus  . The resia fetus .The study successfully evaluated the prevalence rate of macrosomia and its maternal and neonatal complications during 5 years. This study showed that the incidence of macrosomia was 9% during 5 years. The result was comparable with the study conducted by Ehrenberg et al. in 2004 in Ohio, US, that found that the prevalence of macrosomia was 11.8% of population sample . The newThe current study showed that maternal age of 35 years and older was 60% in macrosomia group compared to control group (21%) and is a risk factor for macrosomia. It was comparable with 9.6% in a study by Hajy-Ebrahim-Tehrani et al. . MaternaP < 0.0001) [P < 0.05) which was comparable with  [Our study pointed out that maternal obesity was associated with macrosomia, and it was 75% in the study group as compared to the control group (16%). Obese women were more at risk for macrosomic infants' delivery. It was noted in another study that obese mothers were at elevated risk for large for gestational age (LGA) delivery as compared to normal weight mothers  . Multipa 0.0001) .In the current study the result revealed that history of a previous macrosomia in macrosomic group was 18% compared to control group (1.3%). There are many studies reporting that the history of a pervious macrosomic baby is the most common leading maternal factor to macrosomia . The resThe incidence of Cesarean section in the macrosomic group of our study was 89% compared to the control group (11%). The Caesarean delivery is justified in all cases of fetal weight estimation greater than 4500 g . The ratIt was observed in the current study that maternal complications such as uterine atony (11%), cervix/vaginal laceration (4.9%), and uterine rapture (0.4%) were significantly associated with macrosomia. Another study involved in Saudi Arabia found that the most common maternal complications were postpartum hemorrhage (1.2%), perineal tear (1.7%), and cervical lacerations (0.7%) . The risThe current study pointed out that prevalence of shoulder dystocia, brachial plexus injury, clavicle fracture, and brachial fracture among macrosomic neonates was 11%, 1.9%, 0.6%, and 0.3%, respectively. Our result was confirmed by 9.6% for shoulder dystocia, 0.96% for Erb's palsy and 1.4% for bone fracture . It was Although no intervention has been proven to significantly reduce the risk of macrosomia, several potentially useful strategies may be helpful. In diabetic patients, tight glucose control before pregnancy can reduce the risk of congenital malformation. In both diabetic mothers and in those with gestational diabetes, tight control during pregnancy with the use of diet and insulin can reduce the frequency of macrosomia. Prevention of maternal obesity before pregnancy may reduce the frequency of macrosomia. The rate of perinatal and maternal morbidity can be reduced by the antenatal diagnosis. The risk factors leading to macrosomia must be thoroughly evaluated by the clinician. Since the majority of factors which lead to the delivery of macrosomic infants are preventable, it is hoped that with close cooperation of gynecologists, pediatricians and dieticians along with training of mothers, the number of such incidences would be minimized.


Many physicians are perplexed with an acute increase in the rate of pregnancies and live birth, and a decrease rate of abortions among the women in the Washington DC area. Healthcare managers are analyzing the admission and discharge data to understand this trend. There are many factors such as marital status, age, income, health problems during pregnancy, insurance coverage and other treatment expenses, existence of psychological and emotional problems, patients experience while stay at hospital, and most importantly the increasing cost of abortion that can lead to this sudden increase in rate of live birth and subsequent decrease in the abortion rate in Washington DC area.The main objective of this study is to study the factors that lead to this increase in the rate of pregnancies and live birth, and decrease in the rate of abortion in the Washington DC area.A qualitative approach is used to evaluate and determine the factors that have lead to this increased rate of pregnancies and live child births in Washington, DC area. The Data mining, clustering and statistical techniques were used to evaluate the Casemix datasets to understand the causes increased rate of pregnancies, live birth and reduce rate of abortions in Washington, DC area. Eight hospitals in Washington DC area were randomly selected and included in this study. The Casemix data set of the patient giving live birth at these eight hospitals were abstracted and studied from January to December 1992. The associated patterns leading to the increased rate of live birth and decrease rate of abortions are discovered for further analysis with K means clustering and other statistical techniques.The cost of abortion is the main factor, among the positive factors, that has lead to an increase rate of live births among the cases studied. The unmarried women who cannot afford the cost of abortion were ranked among the highest to continue with the pregnancy whereas the rate of live birth was lowest among the married women’s.This type of information will provide the basis for the proper strategic planning and can help establish policies to provide assistance to the unmarried women’s for abortions or a different policy’s to remove the cost of burden for abortion. The study may help to develop policies that can lead to a decrease in the rate of live births due to increase in cost of abortion.


The combination of homozygosity for the G-allele  and higher birth weight was associated with smaller volume. Furthermore, birth weight was positively associated with cerebellar white matter volume in controls, but not ADHD (interaction: p = .021). The interaction of genotype with birth weight affecting cerebellum gray matter is consistent with models that emphasize increased influence of genetic risk-factors in an otherwise favorable prenatal environment. The absence of an association between birth weight and cerebellum white matter volume in ADHD suggests that other genetic or environmental effects may be at play, unrelated to XKR4. These results underscore the importance of considering environmental effects in imaging genetics studies.This study investigates the effects of XKR4, a recently identified candidate gene for Attention-Deficit/Hyperactivity Disorder (ADHD), birth weight, and their interaction on brain volume in ADHD. XKR4 is expressed in cerebellum and low birth weight has been associated both with changes in cerebellum and with ADHD, probably due to its relation with prenatal adversity. Anatomical MRI scans were acquired in 58 children with ADHD and 64 typically developing controls and processed to obtain volumes of cerebrum, cerebellum and gray and white matter in each structure. DNA was collected from saliva. Analyses including data on birth weight were conducted in a subset of 37 children with ADHD and 51 controls where these data were retrospectively collected using questionnaires. There was an interaction between genotype and birth weight for cerebellum gray matter volume  are associated with ADHD. ► We studied effects of XKR4 and BW on brain volumes in ADHD and controls. ► BW was negatively associated cerebellum gray matter in XKR4 G-homozygotes. ► BW was positively associated with cerebellum white matter in controls but not ADHD. ► Results suggest environmental influence should be considered in imaging genetics. StructuFinally, the XKR4-gene itself has been associated with substance abuse , and a SEnvironmental influences may also be particularly relevant to cerebellum. In previous work in children with ADHD and their unaffected siblings, we have found that familial effects on cerebellum volume were less pronounced than in other brain areas . In addiBirth weight is only moderately heritable, with estimates of its heritability ranging from 10 to 40% . GreaterWe set out to investigate gene and environmental effects, as well as their interaction, on cerebellum volume in ADHD in an hypothesis-driven design. Specifically, we investigated the effects of XKR4-genotype and birth weight, as both of these are likely to have preferential effects on cerebellum. Given the expression pattern of XKR4 in the brain, we hypothesized that the allele previously found to be overtransmitted in ADHD in genetic association studies would be related to smaller cerebellum volume, but not to the volume of other brain measures. Furthermore, we hypothesized that birth weight would affect cerebellum volume independently of XKR4-genotype. In addition, we investigated whether there were interactive effects of XKR4-genotype and birth weight on cerebellum. Given that earlier results from studies investigating gene/birth weight interactions in ADHD mainly suggested effects on comorbid oppositional symptoms, any results showing an interaction between diagnostic group and birth weight were followed up with analyses testing their specificity to subjects with co-morbid ODD.2The Medical Ethical Review Board of the University Medical Center Utrecht approved the study and its procedures.2.1122 Children  aged between 6.6 and 15.7 years participated in this study. Analyses including data on birth weight were conducted on a subset for whom these data were available (51 controls and 37 children with ADHD). The subjects were enrolled in an ongoing longitudinal cohort study of brain development in ADHD. As such, the dataset consisted of new subjects  and subjects who had previously been included in another imaging genetics study  and for whom DAT1 and DRD4 genotype had previously been determined. The previous study did not investigate cerebellum or any genes other than the two mentioned . The remGroups were matched for age, gender and IQ at the group level. Demographic and clinical characteristics are given in 2.2All subjects participated in an MRI-scan on a 1.5 T scanner . The imaging protocol and processing pipeline have been previously reported . BrieflyAll brain scans were coded to ensure rater blindness to subject identity and diagnosis. The T1 images were automatically placed in Talairach orientation  without We conducted exploratory analyses to assess whether the difference in scan type (change in slice thickness and scanner type) between early and later scans significantly affected the volumetric measures see . In mostWe conducted exploratory analyses to assess whether the difference in scan type (change in slice thickness and scanner type) between early and later scans significantly affected the volumetric measures . In most part, the results suggest that our findings cannot be attributed to this methodological issue. The scan slice thickness effect appeared greatest for cerebellum white matter, but for the findings remained very similar whether or not the slice thickness covariate was included in the model. This suggests that the group-level results are robust against the effect of scan slice thickness. In addition, the collection of data over 10 years suggests that drift or scanner updates may have affected the measured volumes. However, as these factors affect both control and ADHD groups equally this will lead to a systematic error and is not likely to result false positives in between-group comparisons. In Supplementary Material 2 we report some further descriptive analyses to address these issue.2.3DNA was collected using buccal swabs as described previously . We sele2.42, independent samples t-tests and Mann–Whitney U-tests as appropriate. We tested for association with ADHD in our samples by using Chi2 tests on allele counts. We then investigated effects of the SNP on volumetric measures using univariate GLM for all volumes separately with age, gender, and scan slice thickness as covariates. The effect of T1 slice thickness on MR-based volumes was systematic and equal for patients and controls. As such, a covariate adequately adjusted the analyses for its effects . Main effects of diagnostic group (control/ADHD), genotype and their interaction were entered into the analysis. If the group by genotype interaction was not significant, this term was removed from the model in order to investigate whether genotype affected the brain volumes regardless of diagnostic status. The XKR4 rs2939678 SNP was recoded to a dichotomous A-carrier versus GG measure, as the number of subjects with the AA genotype was low in both groups .We tested for differences in demographic indices using Chi effects . There wWe also computed an index of birth weight standardized by gestational duration by z-transforming birth weight divided by gestational duration. All analyses were repeated with this measure instead of birth weight, but yielded near-identical results. Therefore, we report only the analyses for birth weight.p-value. If the amount of variance explained by the model (adjusted R2) increased when a second order interaction was removed, this interaction was considered a suppressor term and was not carried forward. As such, the final models reported include either all main effects (in order for the reader to appraise their separate effects), or all main effects and the remaining second or third order effects obtained after the model selection procedure described above. The results section explicitly describes the procedure for each result. We then ran a further multivariate GLM, to further investigate complex effects.We investigated the interactive effects using a univariate GLM approach. For each brain volume, we specified a model with age, gender and scan slice thickness as covariates, main effects of group, genotype and birth weight, all second order interactions and the third order interaction (group × genotype × birth weight). Whereas power to detect third order interaction effects was admittedly limited in the current study, the presence of third order interactions would have significant implications and they were therefore included in the first step of the analytic procedure, for exploratory purposes. If the third order interaction was not significant, it was removed from the model in order to test the presence of second order interactions. If these did not approach significance, they were also dropped from the model in order to investigate main effects. If one or more of the second order interactions approached significance, it was further tested whether these were independent of other second order interactions in the model by dropping the other second order interactions, starting with the interaction with the largest 33.13.2p > .601). However, we found a main effect of XKR4-genotype on cerebellar white matter, both when the group by genotype interaction was included in the model  = 4.21, p = .040) and when it was dropped  = 4.30, p = .038; reduced to p = .064 with intracranial volume as an additional covariate). The GG genotype was associated with smaller cerebellar white matter volume across diagnostic groups  = 50.2(8.1) ml; GG, M(SD) = 45.9(7.2) ml). There were no other main effects of XKR4-genotype .We found no interaction between XKR4-genotype and diagnostic group for any of the volumes tested . The diagnostic groups did not differ in birth weight . This appeared to be a real and independent effect that was suppressed by other non-significant two-way interactions in the model , as stepwise removal of these interactions led to statistical significance of the genotype by birth weight interaction (p = .031 and p = .020 respectively for each removed term), and the variance explained increased with each removal, suggesting that the other two-way interactions were acting as suppressors. In children with the GG genotype, cerebellar gray matter volume was negatively associated with birth weight, regardless of diagnostic group.p = .031), but no other significant interactions or main effects. This interaction was independent of the other factors in the model as it retained significance when the other interactions and main effects were consecutively dropped . However, retaining the diagnostic group by genotype interaction in the model resulted in a marginally higher R2 than the model without this interaction (R2 = .365 and R2 = .362 respectively). Therefore we retained this interaction in the model, even though it did not reach significance . The significance level for the interaction between diagnostic status and birth weight for cerebellar white matter remained similar (p = .021).When total brain volume was added as a covariate in the analyses of cerebellum, the significance level for the interaction between birth weight and XKR4 genotype for cerebellar gray matter increased . The tests for between subject effects showed that a genotype by birth weight interaction was only present for cerebellum gray matter (p = .011) but not white matter (p = .454). A diagnosis by birth weight effect was only present in cerebellum white matter . Next to these interaction effects, a main effect of genotype was only found in cerebellum gray matter (p = .010), but not white matter (p = .624) (p < .10), most likely as a result of the reduced power in such a model. At the subsequent univariate level, both interactions retained significance at p < .05.To further investigate the complex effects on cerebellum gray and white matter, we modeled these volumes together in a multivariate GLM, including both the diagnosis by birth weight and the genotype by birth weight interactions and total brain volume as a covariate. This model had reduced power compared to the univariate ones, but did permit us to address possible interactions between the results found in the univariate tests. In the multivariate tests, both interactions, as well as the main effect of genotype retained significance  . Results4Our results suggest that both XKR4-genotype and birth weight may affect cerebellum volume in ADHD. XKR4-genotype affected the relationship between birth weight and cerebellar gray matter independently of diagnostic group, where subjects with the GG-genotype showed an inverse relationship between birth weight and cerebellar gray matter volume that was absent in carriers of the A-allele. In typically developing children, there was a positive correlation between birth weight and cerebellar white matter volume that was absent in ADHD. This study builds on existing knowledge on cerebellar involvement in ADHD, a replicated finding in neuroimaging studies in ADHD . The cerThe relationship between XKR4-genotype and cerebellum volume is complex: when investigated in isolation, XKR4-genotype appeared to be associated with cerebellar white matter volume. It was not until it was analyzed with birth weight that its effects on cerebellar gray matter became apparent. An effect on gray matter is more consistent with the expression pattern of the related XK-protein, which is found in gray but not white matter . In subjImportantly, we do not find a G × E interaction operating directly on ADHD. Rather, we find evidence for a G × E interactive effect on a quantitative neurobiological marker of ADHD across diagnostic groups. This is important, as G × E effects on diagnosis per se (dichotomized as control and ADHD-group) are vulnerable to a high false positive rate . One wayImportantly, we do not find a G × E interaction operating directly on ADHD. Rather, we find evidence for a G × E interactive effect on a quantitative neurobiological marker of ADHD across diagnostic groups. This is important, as G × E effects on diagnosis per se (dichotomized as control and ADHD-group) are vulnerable to a high false positive rate . One wayWe found an effect of birth weight on cerebellar white matter volume that was dependent on diagnostic group: in controls, higher birth weight was associated with greater cerebellar white matter volume. This relationship could not be detected in ADHD . For conThe current study is modest in size compared to the large datasets in genetic studies of ADHD. However, it was designed as a hypothesis-driven study to investigate specific gene and environmental effects in an intermediate phenotype related to ADHD (i.e. brain changes), rather than aimed at studying associations between gene and behavior in a more exploratory design. As such, its requirements in terms of sample size are more modest, as a phenotype more proximal to gene expression is being investigated . That saThe current study is modest in size compared to the large datasets in genetic studies of ADHD. However, it was designed as a hypothesis-driven study to investigate specific gene and environmental effects in an intermediate phenotype related to ADHD (i.e. brain changes), rather than aimed at studying associations between gene and behavior in a more exploratory design. As such, its requirements in terms of sample size are more modest, as a phenotype more proximal to gene expression is being investigated . That saPrenatal exposure to cigarettes and alcohol are important factors that may affect birth weight , and werAs a final consideration, we would like to remind the reader that the XKR4 gene, despite its suggestive association with ADHD and evidence for preferential cerebellar expression is still a largely uncharacterized gene. Much of what we currently know about the gene derives from knowledge on the related XK-gene and XK-protein, a deletion of which leads to McLeod syndrome . DespiteIn sum, we show that XKR4-genotype and birth weight both affect cerebellum volume, that some of their effects are interactive and that aspects of these effects differ between ADHD and controls. Furthermore, our results were only fully evident when both genetic and environmental factors were considered. This underscores the importance of considering environmental influences in tandem with genetic effects.An analysis of our data using a dimensional measure of ADHD symptoms rather than diagnosis, showing some issues with to such an approach.The effects of scan type/slice thickness on the data.The following are the supplementary materials related to this article.http://dx.doi.org/10.1016/j.nicl.2012.11.010.Supplementary data to this article can be found online at Prof. Durston received a research grant from Unilever Foods which is unrelated to the present study. The other authors report no potential conflicts of interest.


Thyroglossal duct cyst presents most frequently in the midline of the neck, either at or just below the level of the hyoid bone. They generally manifest as painless neck swelling, and they move on protrusion of tongue and during swallowing. A case of thyroglossal cyst was reported in the left submandibular region in a 14-year-old girl, above the level of hyoid bone; ultrasound examination favored a cystic lesion which moved in a vertical fashion on swallowing whereas fine needle aspiration cytology report was suggestive of simple cystic lesion of thyroglossal cyst. No lymphoid or malignant cells were present. The cyst was excised completely by surgical procedure under general anesthesia. Histopathological analysis revealed thyroglossal cyst showing columnar and flattened epithelium of cyst with focal aggregate of chronic inflammatory cells supported by fibrocollagenous cyst wall. The clinical, ultrasound, and histopathological findings suggested that the lesion was an infected thyroglossal cyst. There was no evidence of recurrence 6 months after surgery. The primitive thyroid gland originates from the foramen cecum present in the floor of the pharyngeal gut on the 17th day of gestation. The gland then descends in front of the pharynx as a bilobed diverticulum which is initially patent. It reaches its final position in the neck by the 7th week of the gestation. During migration it is connected to the tongue by a narrow tubular structure—the thyroglossal duct. The duct usually disappears by the 10th week of gestation . The thyroglossal cyst is the commonest congenital neck mass in children, accounting for 70% of congenital neck anomalies and second most benign neck mass, after lymphadenopathy . On preoOur objective is to present a rare case of infected thyroglossal duct cyst in left submandibular region.A 14-year-old girl from the low socioeconomic status, resident of rural area presented to Department of Oral-Medicine & Radiology, Sharad Pawar Dental College & Hospital, DMIMSU, Sawangi, Wardha, India, with the chief complaint of swelling on the left submandibular region with sore throat since 1 month. She has experienced pain in the same region while swallowing. The patient was afebrile with the temperature, pulse, blood pressure and respiration within normal limits. On examination, a 1.5 × 1.5 cm swelling was palpated under the middle one third of left Submandibular region; which was soft and slightly tender on palpation. The overlying skin was comparable with normal wheatish adjacent skin color. The swelling was mobile in vertical direction on swallowing . IntraorIntraoral periapical radiographs with 34, 35, and 36 were within normal limits. Ultrasonographic examination of submandibular swelling showed well-defined cystic lesion with thick wall measuring 1.13 × 1.27 cm . UltrasoThe most common congenital anomaly related to thyroglossal duct is the thyroglossal duct cyst (TDC) located in the region of the hyoid bone. About 15 to 50% are at the level of hyoid bone, 20 to 25% are suprahyoid, and 25 to 65% are infrahyoid . No gendIn the vast majority of cases, ultrasound supplemented by fine needle aspiration cytology is adequate for pretreatment assessment . FNAC seMucous glands and thyroid follicles are commonly seen in the subjacent stroma. Secondary inflammatory changes are usually found. The cytological findings of a thyroglossal cyst are similar to those of a thyroid cyst. However, squamous epithelial cells are usually not noticed as components of a thyroid cyst. This may be the only significant cytomorphologic difference between a thyroglossal duct cyst and a thyroid cyst . DetaileThe typical sonographic description of a thyroglossal duct cyst has been that of an anechoic, well-circumscribed cyst . The pseIn the present case, the history of sore throat and pain on swallowing was suggestive of infected cyst. The cyst moved during swallowing and on protrusion of tongue which directed the diagnosis towards thyroglossal duct cyst. Moreover, the histopathological report has established confirmed diagnosis with its characteristic features.


We aimed to examine evidence for an infectious aetiology among teenagers and young adults (TYA) by analysing monthly seasonality of diagnosis and birth amongst 15–24 year olds diagnosed with cancer in England.Cases of leukaemia, lymphoma and central nervous system (CNS) tumours were derived from the national TYA cancer register (1996–2005). Incidence rates (IR) and trends were assessed using Poisson regression. Seasonality of diagnosis and birth was assessed using Poisson and logistic regression respectively with cosine functions of varying periods.There were 6251 cases diagnosed with leukaemia (n = 1299), lymphoma (n = 3070) and CNS tumours (n = 1882), the overall IR was 92 (95% CI 89–96) per 1,000,000 15–24 year olds per year.P < 0.001) with a peak in February, and for ‘other CNS tumours’ (P = 0.010) with peaks in December and June. Birth peaks for those with ‘other Gliomas’ (Gliomas other than Astrocytoma and Ependymoma) were observed in May and November (P = 0.015).There was significant evidence of seasonality around the time of diagnosis for Hodgkin’s lymphoma (Our novel findings support an infectious aetiological hypothesis for certain subgroups of TYA cancer in England. Further work will examine correlation with specific infections occurring around the time of birth and diagnosis within certain diagnostic groups. There is increasing evidence that environmental factors, such as infections, which vary seasonally and occur around the time of cancer diagnosis or around the time of birth, may affect subsequent development of cancer. This hypothesis can be tested by assessing temporal variation in cancer incidence as well as seasonality around the month of diagnosis and the month of birth amongst those with cancer; evidence for seasonality could reflect seasonal variation of infections.Several studies worldwide have looked at seasonal patterns of cancer diagnosis. Summer peaks of ALL diagnoses have been observed amongst children and adults in East Anglia,  as well Previous research has shown evidence for seasonality around the time of birth in relation to childhood cancer. For example, children diagnosed with acute lymphoblastic leukaemia aged 1–6 years in the North of England exhibited seasonality of birth, with peaks in February and March,  and a stNo studies have examined whether there is evidence of seasonality around the time of birth specifically amongst teenagers and young adults (TYA) with cancer, despite a number of papers studying these effects in childhood cancer. Although there are some studies which cover the childhood and adolescent age range for seasonality around the time of diagnosis, non focus solely on teenagers and young adults.We examined evidence for any cyclical variation in temporal trends in TYA cancer incidence as well as monthly variation in months of diagnosis and birth, using a national cancer register of TYAs in England. We report findings from the first study to examine seasonality of cancer around birth and diagnosis specifically focused on the TYA age group, and as such we explored seasonal patterns in the three main tumour groups  and their major subtypes for which evidence of seasonality already exists within the childhood cancer literature.Cases of leukaemia, lymphoma and central nervous system (CNS) tumours amongst 15–24 year olds diagnosed between 1996 and 2005 in England were obtained from the national TYA database. Data for this study were provided by the North West Cancer Intelligence Service following approval for the release of this information from the National Information Governance Board for Health and Social Care. Ethical approval for this study was obtained from Bradford Research Ethics Committee (Ref: 09/H1302/37). Yearly population data for 15–24 year olds by gender between 1996 and 2005 and month-specific birth populations per year from 1972 to 1990 were obtained from the office for national statistics. Birth populations by month and sex were not available, therefore, the distribution of males and females by year was used to estimate sex-specific birth population estimates for each month.Incidence rates and trends were examined overall and by diagnostic subgroups. Incidence rates per 1,000,000 per year and 95% confidence intervals (CI) were calculated using yearly population figures from 1996–2005 and adjusted for sex. Incidence trends were assessed by deriving the average annual percentage change (AAPC) in incidence rates using sex-adjusted Poisson regression models, cyclical trends were assessed using Joinpoint regression analysis .Seasonality of diagnosis was assessed by modelling the number of diagnoses by month using Poisson regression with the inclusion of cosine curves of 12 and 6 month periods (harmonic curves). Seasonality of birth was assessed by modelling the number of cases born in a certain month compared to the total monthly birth population at risk using logistic regression with the inclusion of harmonic curves of 12 and 6 month periods. As our data is restricted to both the age range at diagnosis and the year of diagnosis (15–24 year olds diagnosed between 1996 and 2005), the birth population at risk for each year is calculated as follows;j ranges from 1972–1990, n is the total number of diagnosis years  and α is the possible age for those born in year j who fall into the 15–24 age range between 1996 and 2005.Where birth year For example, a person born in January 1973 will be aged 23 in 1996 and 24 in 1997. Thus the birth population at risk in January 1973 is Alongside goodness of fit statistics, we calculated Akaike’s information criterion (AIC) to determine the best fitting model in each case. The analysis was completed for all cases of leukaemia, lymphoma and central nervous system (CNS) tumours combined, as well as each major tumour group and subgroup as defined by the classification scheme for tumours diagnosed in adolescents and young adults . Models There were a total of 6251 cases of leukaemia, lymphoma and central nervous system tumours diagnosed amongst 15–24 year olds between 1996 and 2005 in England. Table P = 0.008) which was driven by Hodgkin’s lymphoma (P < 0.001) with peaks in February, and a 6 monthly seasonal effect in those diagnosed with other CNS tumours (P = 0.010) with peaks in December and June  and Hodgkin’s lymphoma  and seasonality with a 6 month cycle for male diagnosis of astrocytoma  and other CNS tumours   and Hodgkin’s lymphoma , and evidence of a 6-monthly seasonal effect of medulloblastoma diagnoses  Table  P < 0.00 with peaP = 0.015)  and CNS tumours ; no seasonality was present in females  Figure . The gooThis is the first national population based analysis in England which focuses specifically on seasonality of birth and diagnosis amongst TYAs with cancer.There is existing evidence of seasonality around the time of diagnosis in children with leukaemia, Hodgkin’s lymphoma and brain tumours as well as some evidence of seasonality of birth for childhood leukaemia. An infectious aetiology for childhood cancers has been found in some diagnostic groups. Our study supports an infectious aetiological hypothesis for certain subgroups of cancer in TYAs in England.Our findings show significant evidence of seasonality by month of diagnosis such that TYAs with Hodgkin’s lymphoma were most likely to be diagnosed in February. This pattern was further confirmed in subgroup analysis by gender for both males and females, and is consistent with that of a previous study looking at both children and adolescents under the age of 20 in Denmark which showed a peak of Hodgkin’s Lymphoma in March . Two furAlthough no specific infectious agent has been identified as a cause for Hodgkin’s lymphoma, there have been numerous studies which have reported an association between Hodgkin’s lymphoma and Epstein-Barr virus (EBV). Mononucleosis is a viral infection usually caused by EBV, which has been shown to have similar seasonal patterns as that of Hodgkin’s lymphoma amongst those under the age of 40, with a peak in March .TYAs diagnosed with tumours classified as ‘other CNS tumours’ displayed a significant winter and summer peak overall, which appeared to be driven by males. Winter peaks have been observed in previous childhood studies of CNS tumours,  but not The bi-modal seasonal birth peaks observed in other CNS tumours (excluding Ependymomas and other Gliomas) and those amongst males with astrocytoma are a surprising result given the wide spectrum of clinical behaviours within both of these heterogeneous groups, which include both low and high grade brain tumours. Infections tend to display seasonal winter peaks, however, there may be a significant lag time between when the first cancer symptoms occurred and the date of diagnosis. Studies looking at the lag time for brain tumours in the TYA age range give inconsistent results, with a median reported delay of around 6 weeks in one paper  and a meAdditionally, we observed a peak in October for male diagnoses of leukaemia. Although childhood studies of seasonality in leukaemia have shown peaks of diagnosis in summer months,  another In addition to seasonality around diagnosis, we also observed significant evidence of seasonality by month of birth. There were significant peaks in the birth months of May and November for males and females who developed ‘other Gliomas’ (Gliomas that are not classified as Astrocytoma or Ependymoma). This finding was difficult to interpret due to the heterogeneous nature of the ‘other Glioma’ classification containing both low grade Gliomas such as Oligodendroglioma and Oligoastrocytoma as well as aggressive high grade Gliomas such as Gliomatosis. Small numbers precluded any further analysis by diagnostic subtype. Further seasonal effects around birth were restricted to males with non-Hodgkin’s lymphoma and males with CNS tumours, both exhibiting peaks in mid-winter and mid-summer.In terms of aetiology, our results suggest that exposures around the time of diagnosis are more important for TYA with cancer than environmental factors operating around the time of birth. This is contrary to epidemiological findings observed amongst childhood cancer diagnosed under the age of 15. This could be evidence for a more important role of environmental factors rather than innate factors alone, due to the increased time period between birth and diagnosis for TYAs compared to children. More generally, a viral infection of the mother transmitted in utero to the foetus may be the precipitating event leading to cancer in adolescence and young adulthood. This mechanism has been described for other chronic diseases including Type I diabetes ,19 and cEvidence of seasonality around the month of diagnosis and month of birth could be explained by a number of factors; they could be a result of increased routine GP/health care appointments in winter leading to higher chances of diagnosis around this time;  or to sePopulation mobility is relatively high for individuals aged between 15–24, with many moving to college or University or entering employment for the first time. This may lead to increased exposure to unknown infections which may vary in ways which might explain the bi-modal seasonality of cancer diagnosis observed within this study.This is the first national population based study in England focusing specifically on seasonality of birth and diagnosis amongst TYAs with cancer. An infectious aetiology for childhood cancers has already been shown in some diagnostic groups, however, this study has produced new findings describing seasonality patterns around the time of diagnosis and birth amongst the TYA age group in England.Our study supports an infectious aetiological hypothesis for certain subgroups of cancer in TYAs in England. We have shown seasonality in diagnosis of Hodgkin’s lymphoma and the other CNS tumour subgroup as well as seasonality in birth for the other glioma subgroup. This work forms the basis for further investigations into the infectious aetiology of TYA cancers by examining correlation with specific infections occurring around birth  and diagnosis within certain cancer subtypes.The authors declare that they have no competing interests.MvL carried out the data cleaning, statistical analysis and drafted the manuscript. SEK and SVP conceived the study and participated in the design and helped draft the manuscript. RGF participated in the design and coordination of the study, helped with the statistical analysis and to draft the manuscript. All authors read and approved the final manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2407/13/365/prepub


Preeclampsia remains a leading cause of maternal mortality and preterm delivery. Both preeclampsia and bronchopulmonary dysplasia (BPD) of prematurity are associated with impaired angiogenesis. However, the relationship between maternal preeclampsia and BPD remains controversial. This study aims to test whether or not preeclampsia is associated with development of BPD in a cohort of premature infants.We conducted a retrospective cohort study assessing the association between preeclampsia and the risk of developing BPD in very-low-birth-weight (VLBW) infants registered in the Premature Baby Foundation of Taiwan from 1997 through 2006. All 21 neonatal departments in Taiwan participated in the data collection. A total of 8,653 VLBW infants were registered in the database. The exclusion criteria included congenital anomalies, chromosome anomalies, infants that died before 36 weeks post-conceptual (PCA), and those whose BPD status were unavailable. BPD was defined as oxygen dependence at 36 weeks postmenstrual age. The association between maternal preeclampsia and BPD was assessed using a multivariate-adjusted logistic regression model.n=847) and the overall incidence of BPD was 34.9%. Infants with maternal preeclampsia had a higher gestational age, higher incidence of cesarean section and being small for their gestational age, lower incidence of respiratory distress syndrome, patent ductus arteriosus, and sepsis. BPD occurred significantly less frequently in the maternal preeclampsia group . Subgroup analysis showed that the association between preeclampsia and BPD was significant only in those VLBW infants with a gestational age between 31–34 weeks.In the end, a total of 5,753 cases were enrolled in this study. The incidence of preeclampsia was 14.7% (This data supports the association between fetal exposure to maternal preeclampsia and a reduced risk of BPD in relatively mature VLBW infants. Preeclampsia results in maternal and fetal morbidity and is a leading cause of preterm delivery ,2. The eIn this report, we examine the association between preeclampsia and the risk of developing BPD in a large multicenter cohort of very-low-birth-weight (VLBW) infants alive at post-conceptual age (PCA) 36 weeks.A total of 8,653 VLBW infants (birth weight less than 1501 g) were born and registered in the database of the Premature Baby Foundation of Taiwan between 1997 and 2006. All 21 neonatal departments in Taiwan participated in the data collection. The data collected included antenatal and perinatal history, infants’ delivery room and neonatal histories including diagnoses, complications during hospitalization, and clinical outcomes at discharge. Patient information received by the database coordinator was cross-checked with the national birth registry. The exclusion criteria included congenital anomalies, chromosome anomalies, infants that died before 36 weeks (PCA), and those whose BPD status were unavailable. Ninety-five infants with maternal chronic hypertension and 38 infants with maternal chronic hypertension with preeclampsia were also excluded. Preeclampsia was defined as a diastolic blood pressure of at least 90 mm Hg accompanied by proteinuria of at least 1+ (30 mg per deciliter) on dipstick testing or nondependent edema during pregnancy . The gesThe written informed consents were obtained from all their designated relatives. The study was approved by the Institutional Review Boards of each participating hospital, including National Taiwan University Hospital, Chang Gung Memorial Hospital, China Medical University Hospital, National Cheng Kung University Hospital, Tri-Service General Hospital, Chung Shan Medical University Hospital, Shin Kong Wu Ho-Su Memorial Hospital, Kaohsiung Medical University Chung-Ho Memorial Hospital, and Joint Institutional Review Board for the other hospitals.Respiratory distress syndrome (RDS) was defined by clinical diagnosis and requiring surfactant therapy. Necrotizing enterocolitis (NEC) was defined using the criteria of Bell , and BPDt-test was used for comparing distributions of categorical variables and the continuous variables between groups, respectively. The multivariate logistic regression model was used to analyze the association between maternal preeclampsia and BPD risk adjusted for potential confounders. The confounders include demographic and clinical variables that were different between those with and without preeclampsia by univariate analysis. Adjusted odds ratios with a 95% confidence interval (CI) were derived to assess the magnitude of the association between various factors and BPD risk. Statistically significant levels were determined using the 2-tailed test (p<0.05). The association between preeclampsia and BPD was further examined in subgroup analysis with stratification according to GA, SGA, Cesarean section, sex, birth weight, singleton, RDS, patent ductus arteriosus (PDA), and Sepsis.The chi-square test and Student’s A total of 5,753 VLBW infants, including 847 (14.7%) cases born to a mother with preeclampsia, were enrolled. The overall incidence of BPD was 34.9%. Infants born to a mother with preeclampsia were more likely to be of higher gestation, delivered via Cesarean section and being female, small for gestational age and of multiple births. They were also less likely to have RDS, NEC, PDA, and sepsis. The incidence of BPD was significantly lower in infants with maternal preeclampsia compared to those without maternal preeclampsia , but not in other GA groups . When weWhen we focused on those extremely preterm infants with a gestational age <28 weeks or birth weight <1000 gm, we found that 11.8% (227/1924) of the infants fell into the preeclampsia group; the incidence of BPD was similar in preeclampsia and control group (56% (127/227) vs. 64% (1083/1697); OR (95% CI): 0.96 (0.67–1.39)). This data indicates that there is no association between preeclampsia and BPD in extremely preterm or extremely-low-birth-weight infants who are at higher risk of developing BPD.In this population-based large cohort study of VLBW infants, we found in overall Taiwanese infants, maternal preeclampsia to be an independent factor associated with a decreased risk of BPD . HoweverRDS is one of the most common diseases in preterm infants and is also a leading cause of subsequent BPD . The relPreviously, Hansen et al. and Korhonen et al. reported that maternal preeclampsia was an independent risk factor for BPD in multivariate analysis (odds ratio (95% CI): 18.7% (2.44–144.76) and 6.75% 1.22–37.3), respectively) ,19. Kurk–37.3, reIn agreement with the report from O’Shea et al. , we founIntrauterine growth restriction or SGA has been reported to be associated with both preeclampsia and BPD ,16,38–44The mechanism of preeclampsia that protects VLBW infants from BPD is not clear. Increasing circulating soluble Flt-1, a soluble form of vascular endothelial growth factor (VEGF) receptor-1 which can bind both VEGF and placenta growth factor (PGF), resulting impairment of angiogenic state was thought to be responsible for the pathogenesis of preeclampsia –6,45–47.The strength of our study was that it was a large multicenter cohort study, allowed us to assess the association between maternal preeclampsia and BPD in several subgroup analyses. Our study also had some limitations. First, the reliability of our data depended on the preciseness of pediatricians and case managers. Second, some data of interest were unavailable in some cases. However, the large size of this database and nondifferential misclassification minimized these influences. Third, the strategies of respiratory care differed among different hospitals. This indeed influences the overall incidence of BPD, but may not lead to bias because the strategy should be the same regardless of whether preterm infants were born to mothers with or without preeclampsia in the same hospital. Fourth, our cohort was defined by birth weight. However, because this could have caused overrepresentation of growth-retarded infants, we performed several subgroup analyses to avoid this problem. Finally, the definition of BPD used here is a traditional clinical definition but not a physiological definition, a discrepancy which reduced the overall rate of BPD and reduced the variation among centers . HoweverIn conclusion, our data supports the association between fetal exposure to maternal preeclampsia and a reduced risk of BPD in the particular subgroup of VLBW infants with gestational age greater than 31 weeks.Table S1The regression analyses on factors associated with RDS.(DOC)Click here for additional data file.


Studies of the genetic and environmental influences on apolipoproteins have been conducted, but few have used data from Japanese twins. The aim of this study was to quantify and compare the genetic and environmental causes of individual differences in the serum concentrations of apolipoproteins in Japanese middle-aged twins.Apo A-I, apo A-II, apo B, apo C-II, apo C-III, and apo E were studied. A total of 142 twin pairs, aged 45 through 65 years, were enrolled: 85 monozygotic pairs  and 57 same-sexed dizygotic pairs . The intraclass correlation coefficient and structural equation modeling were used to estimate the best-fitting model and heritability.Sixteen percent to 75% of the total variances of apo A-I, apo C-II, and apo C-III were attributable to genetic influence; apo A-I and apo C-II were influenced by dominant genetic factors. Twenty percent to 73% of the total variances of apo A-II, apo B, and apo E were attributable to additive genetic influence; apo B was clearly influenced by common environmental factors. Furthermore, the heritability of all apolipoproteins was higher among females than among males.Genetic factors, including additive genetic effects (A) and dominant effects (D), influence apolipoprotein levels. However, a common environment does not influence the variances of these apolipoproteins, with the exception of apo B. Furthermore, the heritability of apolipoprotein phenotypes differs by sex. Apolipoproteins are proteins that bind to fats (lipids) to form a lipoprotein. They are synthesized in the liver and intestine and form lipoproteins that transport dietary fats through the bloodstream. Apolipoproteins also serve as enzyme cofactors, receptor ligands, and lipid transfer carriers that regulate the metabolism of lipoproteins and their uptake in tissues. There are 6 major classes of apolipoproteins, and several sub-classes. These include A , B (apo B48 and apo B100), C , D, E, and H. In the present study, A (apo A-I and apo A-II), B (apo B48 and apo B100), C (apo C-II and apo C-III), and E were studied.Apolipoprotein A-I is the most abundant protein in high-density lipoproteins (HDL), and there is an inverse relation between both HDL-cholesterol and plasma apo A-I levels and the risk of coronary heart disease (CHD).1In humans, apo A-II is the second most abundant apolipoprotein in HDL. It has been hypothesized that apo A-II is not a strong determinant of lipid metabolism, but that it is instead a modulator of reverse cholesterol transport.Apolipoprotein C-II is found in chylomicrons  and very low-density lipoprotein . Apo C-II activates the enzyme that breaks down chylomicrons and VLDL molecules.Apolipoprotein C-III is a VLDL protein that inhibits lipoprotein lipase and hepatic lipase, and is believed to delay catabolism of triglyceride-rich particles. An increase in apo C-III level induces hypertriglyceridemia.Apolipoprotein B is a form of low density lipoprotein (LDL), and plays a role in metabolism.2 More recently, investigators have focused on its role in several biological processes not directly related to lipoprotein transport, including Alzheimer's disease (AD), immunoregulation, and cognition.3–6Apolipoprotein E is a serum protein that is involved in the transport, storage, and metabolism of cholesterol. Apo E was first recognized for its importance in lipoprotein metabolism and cardiovascular disease.7–9 few have analyzed Japanese twins. Therefore, the aim of this study was to quantify and compare the genetic and environmental causes of individual differences in serum apolipoprotein levels in Japanese middle-aged twins.In Japan, the twin birth rate is approximately 4 twin pairs per 1000 newborn infants. Twin studies are valuable because monozygotic (MZ) twins share an identical genotype, whereas dizygotic (DZ) twins are no more alike genetically than siblings, who share an average of 50% of their segregating genes. If MZ twins display a greater resemblance for a specific trait than do DZ twins, it is likely to be attributable to genetic factors. Although there have been studies of the genetic and environmental influences on apolipoproteins,The twins participating in this study were recruited from the cohort of the nationwide, population-based, Osaka University Aged Twin Registry (OUATR) in Japan. Twin pairs in the OUATR were recruited in several ways, including newspaper advertisements, posters in hospitals, and referrals from midwives. A total of 188 same-sexed pairs volunteered for this study and underwent a comprehensive medical examination. The ages of the twins varied from 12 to 90 years; most were in their sixth and seventh decades of life. A total of 142 twin pairs aged from 45 through 65 years were chosen as the subjects for this study, including 85 MZ pairs  and 57 same-sexed DZ pairs , as shown in Table This study was approved by the Osaka University Ethical Review Committee.10 Thus, the zygosity status of our source population was determined with an overall accuracy of 95%.When the twin registry was initially compiled, beginning in 1974, zygosity was determined by using the phenylthiocarbamide (PTC) test and tests of 9 blood systems: ABO, Rh , MN , Lewis , P (P1), Duffy , Kidd , Kell (K), and Diego (Dia). This classification methodology is 95% accurate in determining twin zygosity. The use of a questionnaire is also 95% accurate in determining zygosity. Such a questionnaire was used in a study of a Swedish cohort.The twins were instructed in advance not to eat breakfast on the examination day. Ten ml venous blood was taken at the Kinki University Hospital. Apolipoproteins were analyzed by single radial immunodiffusion. All blood analyses were done at the Central Laboratory of Kinki University Hospital in Japan.11Intraclass correlation coefficient (ICC) and structural equation modeling were used to estimate the best-fitting model and heritability.Twin models, including additive genetic effects (A), dominant effects (D), common environmental effects (C), and non-shared environmental effects (E), were examined using the standard correlations between MZ and DZ pairs, ie, the correlation of additive genetic effect was set to 1 for MZ pairs and to 0.5 for DZ pairs and the correlation of dominant genetic effect was set to 1 for MZ pairs and to 0.25 for DZ pairs. The correlation between common environmental effects equaled 1; there is no correlation of nonshared environmental effects between twins. It is assumed that common environmental factors are shared to a similar extent by MZ and DZ pairs. If the MZ twin correlation is more than double the DZ twin correlation, it is possible that dominant genetic effects played a large role in that trait. Because some ICCs of MZ pairs were more than double those of DZ pairs in this study Table , we fit SPSS 13.0 for Windows was used for the statistical analysis. Genetic and environmental sources of variation in the serum levels of apolipoprotein were modeled by MxGui Version 1.7.03.P < 0.05) difference was noted in the levels of all apolipoproteins except apo A-II and apo C-II; all apolipoprotein levels were higher in women than in men. Therefore, subsequent analysis examined differences by sex. Most of the mean apolipoprotein values in this study were higher than the average normal values, but only the apo B value among women exceeded the normal range. We attribute this finding to sampling error.The means and standard deviations of serum apolipoprotein levels are shown in Table P > 0.05, by z test).Table P was higher than 0.05 by the chi-square test. As the results in Table Structural equation modeling was used to estimate heritability. Table The present study investigated the magnitude of genetic and environmental effects on serum levels of apolipoprotein in 142 middle-aged Japanese twin pairs. The importance of the influence of genetic factors on a trait is defined as heritability, ie, the proportion of population variation attributable to genetic variation, including additive genetic effects (A) and dominant effects (D). We found that 16% to 62% and 59% to 75% of the total variances were attributable to genetic factors in men and women, respectively.9,12,13 However, some investigators found no evidence of additive genetic effects.14,15 In addition, it was reported that variations in apo A-I levels that are within the normal range, especially during adolescence, are likely to be influenced by many factors, without any significant contribution from major genes.16Regarding the variance in apolipoprotein A-I level, 39% and 60% was attributable to genetic factors in men and women, respectively. Most studies report heritability estimates between 40% and 80% for apo A-I and apo B, which conforms to our results.9,13,17 which reported that the heritability of apo B ranged from 28% to 78%. Chien et al reported that, among adolescents, variations in apo B levels that are within the normal range are controlled by a major gene.18 In addition, apo B was found to be significantly affected by occupation, alcohol consumption, physical activity, and obesity.19 Apo B is strongly influenced by lifestyle.Concerning apolipoprotein B, 32% and 59% of variance was due to genetic factors in men and women, respectively. This accords with some other studies,20 which conforms with the results of the few previous reports.14,21The heritability of apo E in the present study was 50% and 74% in men and women, respectively. Beekman et al reported that the total variance in apolipoprotein E levels depended largely on genetic factors (from 48% to 87%),22 This estimate accords with our finding that the genetic heritability of serum apolipoprotein A-II was 30% for male twins and 65% for female twins. There are very few studies of the heritability of apo C-II and C-III.19 In the present study, we were unable to obtain exact estimates of the genetic effects on the variance in apo C-II and C-III. We believe that this is the first report of these values: the heritability of apo C-II is 62% in men and 75% in females and the heritability of apo C-III is 16% in males and 67% in females.There are fewer studies of the heritability of apolipoprotein A-II, C-II, and C-III. Hamsten et al reported that the genetic heritability of serum apolipoprotein A-II was 42%, as estimated by path analysis in families selected through probands with premature myocardial infarction and in families randomly selected from the general population.19 that none of these models fitted significantly better than a model that included only an additive genetic and unique environmental factor. Therefore, further twin studies of the dominant genetic factors that influence apolipoprotein should prove informative.When the correlation among DZ twins was less than half the correlation among MZ twins, models including a dominance genetic factor were examined. In the present study, the influence of dominant genetic factors on apo A-I was 39% in males and 30% in females; the influence on apo C-II was 52% in males and 75% in females. However, Beekman reported23 to evaluate the effect of aging on genetic and environmental variation in lipid and apolipoprotein levels, increases in age-related phenotypic variance in total cholesterol and apo B were almost entirely due to the accumulation of unique environmental experiences; no consistent age trends were found for apo A-I. The limited number of available longitudinal studies provide evidence for the existence of age-dependent gene expression for at least some lipids and lipoproteins. New genes are expressed during adolescence,24 and gene expression differs in childhood and adulthood.25 There is a sex-specific influence on variation in apo B levels,18 and a small, but significant, sex difference in heritability of lipoprotein A was observed.26 However, Debra et al reported that there are no sex differences in the relative importance of genetic factors for any of the lipids studied, except apolipoprotein B.27In previous studies, the estimates of the age and sex factors that influence the heritability of apolipoprotein are contradictory, but most results indicate that age and sex play important roles in the heritability of apolipoprotein. For example, in a study that used data from the Swedish Twin Registry28 and that adverse changes in apolipoproteins occur after menopause in women.13 Furthermore, in Japan, middle-aged men usually work, so their environments and lifestyles may differ considerably from each other. By contrast, most women do housework and their living environments and lifestyles may be more similar. Therefore, environmental influences may be stronger among men as compared to women.In the present study, because twin pairs aged younger than 45 or older than 65 years were few—and age significantly influences heritability of apolipoprotein—twin pairs aged from 45 through 65 years were selected as subjects. Among these middle-aged twin pairs, sex differences in the genetic factors influencing apolipoprotein were observed: both heritability and the levels of apolipoprotein were higher in females than in males. We hypothesize that new genes in apolipoprotein are expressed during middle age in women,13,29–32 The importance of shared environmental influences on apolipoproteins during early adulthood suggests that family-based lifestyle interventions could be successful.33 However, in the present study, common environmental factors influenced only apo B. This result accords with a previous study of 1362 twin pairs that concluded that none of the lipid traits was significantly influenced by the presence of a shared environment.27Shared environmental factors are usually regarded as those related to early childhood. Some studies have shown that common environmental factors significantly influenced apolipoprotein traits.The present study did have some limitations. The number of subjects was not large; thus, the 95% confidence intervals were large and the statistical power relatively low. However, we believe that data from 142 twin pairs is not inconsiderable, and should have substantial value as a reference.In conclusion, we found that genetic factors, including additive genetic effects (A) and dominant effects (D), influenced apolipoprotein levels, and that a common environment does not influence the variances of apolipoproteins, with the exception of apo B. Furthermore, the heritability of these apolipoprotein phenotypes differs by sex.