Another classic MIR, asked in 2019 and in 2017, fragile X syndrome. Also, on the same concept as question 44, the phenomenon of genetic anticipation. Triplet expansion diseases, such as this one, can have the anticipation phenomenon whereby females with premutations (between 55-200 repeats) can have children with full mutations (more than 200 repeats of the triplet) and more obvious, more severe and/or earlier clinical, in both males and females (Fragile X syndrome, early ovarian failure, tremor/ataxia associated with Fragile X).

What genetic and reproductive counseling would you indicate to a 30-year-old woman who consults because she is a carrier of a premutation in the FMR1 gene, responsible for Fragile X syndrome, and who wishes to have offspring. Point out the correct answer:

All her male children will be carriers and, therefore, will manifest the disease.

There is a phenomenon of genetic anticipation, so their offspring will present more severe and earlier symptoms.

Preimplantation genetic diagnosis for sex selection of embryos by fluorescence in situ hybridization (FISH) is the best option for healthy offspring.

50% of her daughters will be carriers, but will not present clinical manifestations of the disease.

Preimplantation genetic diagnosis

In the case of families at risk for X-linked diseases, patients are provided with a single PGD assay of gender identification. Gender selection offers a solution to individuals with X-linked diseases who are in the process of getting pregnant. The selection of a female embryo offspring is used in order to prevent the transmission of X-linked Mendelian recessive diseases. Such X-linked Mendelian diseases include Duchenne muscular dystrophy (DMD), and hemophilia A and B, which are rarely seen in females because the offspring is unlikely to inherit two copies of the recessive allele. Since two copies of the mutant X allele are required for the disease to be passed on to the female offspring, females will at worst be carriers for the disease but may not necessarily have a dominant gene for the disease. Males on the other hand only require one copy of the mutant X allele for the disease to occur in one's phenotype and therefore, the male offspring of a carrier mother has a 50% chance of

Preimplantation genetic diagnosis

Another problematic case is the cases of desired non-disclosure of PGD results for some genetic disorders that may not yet be apparent in a parent, such as Huntington disease. It is applied when patients do not wish to know their carrier status but want to ensure that they have offspring free of the disease. This procedure can place practitioners in questionable ethical situations, e.g. when no healthy, unaffected embryos are available for transfer and a mock transfer has to be carried out so that the patient does not suspect that he/she is a carrier. The ESHRE ethics task force currently recommends using exclusion testing instead. Exclusion testing is based on a linkage analysis with polymorphic markers, in which the parental and grandparental origin of the chromosomes can be established. This way, only embryos are replaced that do not contain the chromosome derived from the affected grandparent, avoiding the need to detect the mutation itself.

Enacting genetic responsibility: experiences of mothers who carry the fragile X gene.

A woman who carries the gene for fragile X syndrome (FXS) has a 50 per cent chance per pregnancy of passing the gene to her sons and daughters. In this paper we analyse interview data from mothers who are carriers of the FX gene, and who have at least one child with FXS, to examine how their understandings and enactments of reproductive options, obligations, and responsibilities support an expanded notion of genetic responsibility. Accounts of 108 women from across the United States show that the majority of mothers chose not to have another biological child once they learned their carrier status. They discussed genetic responsibility and reproductive agency in terms of an obligation not to risk having another child who carried the gene, although their accounts reflected the tensions that arose from managing oneself as a genetically at-risk actor. Another 22 mothers either purposely became pregnant or continued an unplanned pregnancy after finding out their carrier status. These mothers' accounts reflect an expanded version of genetic responsibility that incorporates ideas and values beyond managing risk in what it means to act responsibly in light of genetic knowledge.

Preimplantation genetic diagnosis

the disease. Males on the other hand only require one copy of the mutant X allele for the disease to occur in one's phenotype and therefore, the male offspring of a carrier mother has a 50% chance of having the disease. Reasons may include the rarity of the condition or because affected males are reproductively disadvantaged. Therefore, medical uses of PGD for selection of a female offspring to prevent the transmission of X-linked Mendelian recessive disorders are often applied. Preimplantation genetic diagnosis applied for gender selection can be used for non-Mendelian disorders that are significantly more prevalent in one sex. Three assessments are made prior to the initiation of the PGD process for the prevention of these inherited disorders. In order to validate the use of PGD, gender selection is based on the seriousness of the inherited condition, the risk ratio in either sex, or the options for disease treatment.

Preimplantation genetic diagnosis by fluorescence in situ hybridization: clinical possibilities and pitfalls.

Preimplantation genetic diagnosis using the fluorescence in situ hybridization technique (FISH) is being used widely to prevent the transmission of sex-linked diseases, to screen for translocations, and for aneuploidy screening in specific in vitro fertilization (IVF) patient groups, along with FISH analysis of spermatozoa in infertile men. In this study, we aim to critically analyze our clinical results in patients at risk of transmitting sex-linked diseases (n = 55), in carriers of translocations (n = 43), in women who have recurrent miscarriage (two or more miscarriages) (n = 128), recurrent IVF failure (three or more failed IVF attempts) (n = 47), and patients of advanced maternal age (37 years old or older) (n = 79). The use of the FISH technique in carriers of sex-linked diseases and translocation patients prevents transmission of these conditions and provides good IVF outcome. In patients with recurrent miscarriage, implantation failure, and advanced maternal age, a high incidence of embryos with abnormal chromosomes 13,16,18,21,22, X, and Y was observed (range 69-75%), as expected. In those three groups of patients, the selection of euploid embryos for transfer resulted in good pregnancy rates with a low incidence of miscarriage. Limitations and pitfalls of this technique are also discussed.

Carrier testing

The physical risks for getting this kind of genetic testing done are very minimal. The most common requirement is a blood sample. The emotional risks on the other hand are great. When a person finds out they are a carrier for a specific genetic disorder, dealing with that can be very difficult. In many cases, people who find out they are carries can become angered or even enraged that they carry a genetic defect that could be passed on to their child. These results can play a role in determining if a couple will have a child together. If both parents are carriers for the same genetic disorder, there is a twenty-five percent chance that any child they have could be affected. When a person finds out they are a carrier, they are always encouraged to talk to a genetic counselor. If both partners are carriers for the same genetic disease, the choice to have a child together can become much more difficult. IVF with preimplantation genetic diagnosis may be considered, to remove the risk of

A proposal for reproductive counselling in carriers of Robertsonian translocations: 10 years of experience with preimplantation genetic diagnosis.

Carriers of Robertsonian translocations are at increased risk for infertility, repeated miscarriage and aneuploid offspring. In the present study, 10 years of experience with preimplantation genetic diagnosis (PGD) for Robertsonian translocations is reviewed and these data are used to improve the reproductive counselling in the carriers. A retrospective analysis was performed of all requests and cycles for PGD for Robertsonian translocations at our centre between January 1997 and December 2006. Data on the characteristics of the couples and on the PGD cycles were retrieved from the medical records. These data were recorded for the whole group and according to the sex of the carrier. A total of 111 couples made a request for PGD in our centre, of which 76 had at least one PGD cycle. In the PGD cycles embryo transfer could take place in 66.1% of the cycles with oocyte pick-up and positive hCG was found in 42.7% of the cycles with embryo transfer. The live born delivery rate was 20.2% per cycle with oocyte retrieval and 30.5% per cycle with embryo transfer. With a live birth delivery rate of 32.9% per couple, PGD is considered a good option for these couples, especially when there is a coexisting fertility problem. PGD reduces the risk of miscarriage and allows couples to have a healthy child within a relatively short time span compared with spontaneous pregnancies. However, for young, fertile couples, the chances of having a healthy child after a number of spontaneous pregnancies, should not be ignored.

Parental decisions of prenatally detected sex chromosome abnormality.

Because of the widespread use of amniocentesis, the prenatal recognition of sex chromosome abnormality (SCA) has become increasingly common. Recent literature provided an insight into the understanding of the natural history and prognosis for individuals with SCA. Our study was designed to review the parental decision on pregnancy with SCA. Over the last 10 yr, we diagnosed 38 cases (0.50%) with SCA out of 7,498 prenatal cases. We reviewed the records and the results of the pregnancies. We included the cases (n=25) of apparently normal anatomic fetus to analyze the factors influencing parental decision. We excluded 13 cases with obvious anomaly or presumably bad outcome. Fifteen (60%) couples continued their pregnancies and ten (40%) terminated theirs. Nine couples (64%) out of fourteen mosaicism cases continued their pregnancies. All five pregnancies assisted by reproductive technique continued their pregnancies. More pregnancies were continued when counseling was done by an MD geneticist rather than by an obstetrician. A significant trend was observed with a higher rate of pregnancy continuation in recent years. The genetic counseling is important to give appropriate information to the parents. Establishing guidelines and protocols will help both obstetricians and parents to make a decision.

Mohr–Tranebjærg syndrome

Genetic Counseling Since the pattern of inheritance for Mohr-Tranebjærg is known to be X-linked recessive, genetic counseling is considered beneficial to families with known carriers. In the case that a female is a carrier, the statistical risk of male offspring inheriting the disease is 50%, while the probability that a female offspring will be a carrier is 50%. However, when a male is the carrier, the probability of having a female carrier offspring is 100%, and male offspring will not have any chance of inheriting the syndrome. Because of the statistical probabilities that each sex inherits the syndrome, males are affected by Mohr-Tranebjærg more frequently than females are. Females who carry one copy of the TIMM8A gene (described in Genetics) are usually unaffected, however, may develop mild hearing loss and dystonia.

Contacting gamete donors to facilitate diagnostic genetic testing for the donor-conceived child: what are the rights and obligations of gamete donors in these cases? A response to Horton <i>et al</i>.

In their paper Horton <iet al</i argue that it is acceptable to contact an anonymous egg-donor to facilitate diagnostic genetic testing for the donor conceived child, despite the donor, 'indicating on a historical consent form that she did not wish to take part in future research, and that she did not wish to be informed if she was found to be a carrier of a "harmful inherited condition"'. There are a number of claims embedded in Horton <iet al</i's position that it is acceptable to contact the donor and request that she at least think about participating in genetic testing. In this response. I will go through their main claims and argue that the area of genomic medicine does not justify exceptions to general consent conditions as the authors suppose and conclude that the donor should not be contacted. I will then go on to suggest a policy change that would address Horton <iet al</i's concerns but would not involve over-riding any previously expressed wishes.

Scientific aspects of preconception gender selection.

Although numerous methods have been promoted as having an influence on the gender of offspring, most lack credible scientific evidence of effectiveness. Preconception gender selection has an important application in reducing the risk of having children with X-linked disease. A preconception, flow cytometric sperm sorting method of gender selection (MicroSort) is based upon the detection of differential fluorescence emitted by fluorescently stained X and Y chromosome-bearing spermatozoa. Ongoing clinical trial results illustrate the safety and efficacy of the method. Fluorescence in-situ hybridization (FISH) analysis of specimens pre- and post-sort show the 50:50 X:Y ratio in unsorted spermatozoa can be shifted to 90% X or 75% Y after sorting. Embryo gender and fetal/baby gender are consistent with post-sort FISH results. Intrauterine insemination (IUI) and IVF/ICSI (intracytoplasmic sperm injection) pregnancy rates are consistent with those reported in the assisted reproduction literature. Clinical loss rates are similar to those in the general population. The observed major congenital abnormality rate of 2.05% for babies born after using this sperm sorting method coincides with that occurring spontaneously. Current results indicate that the method is a safe and effective process and is a valuable tool for families wishing to balance the gender distribution of their children or to reduce the likelihood of having children with X-linked disease.

Prenatal carrier testing for fragile X: counseling issues and challenges.

Healthy women who carry a ''premutation'' in the FMR1 gene (or fragile X mental retardation protein) can pass on a further mutated copy of FMR1 to either male or female offspring, leading to fragile X syndrome (FXS). Premutation carriers do not have manifestations of FXS in cognitive deficits, behavioral abnormalities, or classic physical features, but are at increased risk for development of the ''fragile X-associated disorders'': premature ovarian insufficiency and fragile X-associated tremor and ataxia syndrome. When considering widespread prenatal carrier screening programs for fragile X, significant resources must be available for at-risk individuals, including counseling, accurate diagnostic options for fetal testing, and choice regarding continuation of a pregnancy. Further attention is needed to develop and utilize inexpensive screening tests with adequate sensitivity and specificity to reduce barriers to screening for the population. Recently newer methodologies for high-throughput and inexpensive screening assays, which correctly detect expanded alleles in premutation and full mutation patients with a high degree of sensitivity, show significant promise for reduction in cost with rapid turn around times. With the introduction of widespread screening, individuals will be made aware not only of their risk for offspring with FXS, but will also have knowledge of the potential risk to develop the adult-onset conditions- FXPOI and FXTAS. This introduces more complex counseling challenges. All individuals identified as carriers of intermediate or premutation alleles should be referred for genetic counseling to properly convey risks for allele expansion and to discuss possible future risks of fragile X-associated disease.

[X maternal mosaicism and genetic counseling].

Among number of women having consulted for repeated miscarriages about sixty have a gonosomic mosaicism involving chromosome X for which abnormal clones (monosomy and/or excess) are always the minority. A retrospective study of the obstetrical follow up these patients have shown that 23% of them will give birth to a child with a chromosomic abnormality (21 trisomy, 13 trisomy, 45,X, 45,X/46,X iso X (q), 48,XXXX, 49 XXXXXY, del 5 p-). The hypothesis of a tendency toward non-disjunction is pushing for an prenatal diagnosis for patients with X mosaicism. However one can question about the real meaning of this abnormality regarding to the fact that the patients referred are not representative of the general population. Should interchromosomic interaction be taken for responsible? Is the risk for having a child chromosomic abnormality, especially X aneuploidy the same than for the overall population. It certainly would be rewarding to look after these different hypothesis in a multicentric collaborative study.

Fragile X syndrome

This disorder and finding of Fragile X syndrome has an X-linked dominant inheritance. It is typically caused by an expansion of the CGG triplet repeat within the FMR1 (fragile X mental retardation 1) gene on the X chromosome. This results in silencing (methylation) of this part of the gene and a deficiency of the resultant protein (FMRP), which is required for the normal development of connections between neurons. Diagnosis requires genetic testing to determine the number of CGG repeats in the FMR1 gene. Normally, there are between 5 and 40 repeats; fragile X syndrome occurs with more than 200. A premutation is said to be present when the gene has between 40 and 200 repeats; women with a premutation have an increased risk of having an affected child. Testing for premutation carriers may allow for genetic counseling.

'Designer babies' almost thirty years on.

The first pregnancies and live births following <iin vitro</i fertilisation (IVF) and preimplantation genetic testing (PGT), formerly known as preimplantation genetic diagnosis, were reported in 1990, almost 30 years ago, in several couples at risk of X-linked inherited conditions, which typically only affect boys inheriting the X chromosome with the affected gene from their carrier mothers. At that time, it was only possible to identify the sex of the embryo by amplifying a Y-linked repeat sequence in single cells biopsied at cleavage stages and avoid the transfer of males, half of which would be affected. The extensive publicity surrounding these cases and the perceived risk of using IVF and PGT for desirable characteristics not related to health, such as sex selection, led to the epithet of 'designer babies' which continues to resonate to this day. Here, I briefly reflect on how the technology of PGT has evolved over the decades and whether it deserves this reputation. With efficient methods for whole genome amplification and the genomic revolution, we now have highly accurate universal tests that combine marker-based diagnosis of almost any monogenic disorder with the detection of aneuploidy. PGT is now clinically well established and is likely to remain a valuable alternative for couples at risk of having affected children.

Norrie disease

Genetics Norrie disease is a rare genetic disorder caused by mutations in the NDP gene, located on Xp11.4 (GeneID: 4693). It is inherited in an X-linked recessive manner. This means that almost only males are affected. Sons of affected men will not have the mutation, while all of their daughters will be genetic carriers of the mutation. Female carriers usually show no clinical symptoms, but will pass the mutation to 50% of their offspring. Daughters with the mutated gene will also be, like their mother, asymptomatic carriers, but 50% of their sons will express clinical symptoms.

[Methods of sex selection. A new method for preventing genetic diseases].

Determining sex of offspring has been a subject of intense interest for the public and professional community. Although methods of selecting sex before concepts are not entirely reliable, couples could satisfy their wishes for the size and composition of their family and the children might benefit by being wanted. On the other hand, the ability to selectively separate X from Y chromosome-bearing spermatozoa and use the X spermatozoa to preferentially produce female offspring; could be reduce, or may even eliminate, the probability of conceiving affected males of X-linked diseases.

Nagwa Abdel Meguid

Meguid developed a simple molecular screening method to detect premutation carriers of fragile X syndrome. A premutation carrier is an individual who has between 55-200 CGG repeats in the Fragile X (FMR1) gene. The full mutation has over 200 CGG repeats. The procedure included a rapid modified polymerase chain reaction (PCR)-based screening tool for expanded Fragile X Mental Retardation 1 (FMR1) alleles. The results showed that 16 males out of 53 males had the CGG abnormal repeats characteristic of Fragile X gene. 10 of their mothers and 4 of their sisters also had the FMR1 premutation. 66.6% consanguineous marriages were present in the families studied. It was concluded that fragile X syndrome was ruled out of families with consanguineous parents. Instead, fragile X syndrome could be contributed to earlier carrier detection, which may reduce the number of affected children. By isolating the mutation early, the effects of the disease could be reduced in children and in their

Preimplantation genetic diagnosis: the ethics of intermediate cases.

According to the current guiding principle regarding preimplantation genetic diagnosis (PGD), the technique should focus on the diagnosis of genetic defects which (may) affect the health of this particular potential child--the so-called 'medical model'. I argue in favour of a more permissive view, also allowing PGD of characteristics which may be relevant for the health of 'third parties'. Two cases are analysed: PGD/HLA typing in order to save a sib, and PGD/sex selection in order to prevent the birth of healthy female carriers of X-linked recessive disorders, who are at high risk of conceiving affected sons. While these cases are at odds with the medical model stricto sensu, they do have a link with health problems. In the first case, the health benefit hoped for is intrafamilial, in the second case the health benefit is transgenerational. These cases illustrate that the traditional dichotomy between the medical model on the one hand and the 'designer' or autonomy model on the other hand is simplistic--they represent an intermediate category.

Preimplantation genetic diagnosis for monogenic diseases: overview and emerging issues.

Preimplantation genetic diagnosis (PGD) is an established reproductive option for couples at risk of conceiving a pregnancy affected with a known genetic disease, who wish to avoid an (additional) affected child, termination of pregnancy or recurrent miscarriages. Early technologies concentrated on different approaches to direct mutation testing for monogenic diseases using single cell PCR protocols, or sex selection by fluorescent in situ hybridization for X-linked monogenic disease. Development of multiplex fluorescent PCR allowed simultaneously testing of linked markers alongside the mutation test, increasing the accuracy by controlling for contamination and identifying allele drop-out. The advent of highly effective whole genome amplification methods has opened the way for new technologies such as preimplantation genetic haplotyping and microarrays, thus increasing the number of genetic defects that can be detected in preimplantation embryos; the number of cases carried out and the new indications tested increases each year. Different countries have taken very different approaches to legislating and regulating PGD, giving rise to the phenomenon of reproductive tourism. PGD is now being performed for scenarios previously not undertaken using prenatal diagnosis, some of which raise significant ethical concerns. While PGD has benefited many couples aiming to have healthy children, ethical concerns remain over inappropriate use of this technology.

Wilhelm Weinberg

By the same token, he recognized that ascertainment was responsible for a phenomenon known as anticipation, the tendency for a genetic disease to manifest earlier in life and with increased severity in later generations. Weinberg recognized that this was because those later generations were the offspring of that selected group of earlier carriers that had successfully reproduced. Subsequent researchers have reasoned that such carriers who reproduce might be expected to carry favorable compensatory mutations that allowed them to reproduce successfully in spite of their disease. In a class of autosomal and X-linked dominant diseases known as trinucleotide repeat disorders (for example, Huntington's disease), a molecular mechanism for anticipation has also been demonstrated. It is caused by the instability of repeating nucleotide sequences that tend to undergo expansion, causing disease at an earlier and earlier age as trinucleotide repeats accumulate.

The aims of expanded universal carrier screening: Autonomy, prevention, and responsible parenthood.

Expanded universal carrier screening (EUCS) entails a population-wide screening offer for multiple disease-causing mutations simultaneously. Although there is much debate about the conditions under which EUCS can responsibly be introduced, there seems to be little discussion about its aim: providing carrier couples with options for autonomous reproductive choice. While this links in with current accounts of the aim of foetal anomaly screening, it is different from how the aim of ancestry-based carrier screening has traditionally been understood: reducing the disease burden in the population. The reasons why the aim of EUCS is presented in terms of 'autonomy' rather than 'prevention' have not been spelled out in the literature. This paper seeks to fill this gap by considering the morally relevant similarities and dissimilarities between foetal anomaly screening, ancestry-based carrier screening and EUCS. When carrier screening is performed in the prenatal period, enhancing autonomy appears the most appropriate aim of EUCS, as the alternative of 'prevention through selective abortion' would urge women to terminate wanted pregnancies. However, when screening is conducted in the preconception period, carrier couples can avoid the birth of affected children by other means than selective abortion, for instance preimplantation genetic diagnosis. To the extent that this increased control over passing on a genetic disorder raises questions of parental responsibility, it seems necessary that the account of the aims of EUCS is wider than only in terms of enhancing reproductive autonomy.

Smith–Fineman–Myers syndrome

Genetics SFMS is an X-linked disease by chromosome Xq13. X-linked diseases map to the human X chromosome because this syndrome is an X chromosome linked females who have two chromosomes are not affected but because males only have one X chromosome, they are more likely to be affected and show the full clinical symptoms. This disease only requires one copy of the abnormal X-linked gene to display the syndrome. Since females have two X chromosomes, the effect of one X chromosome is recessive and the second chromosome masks the affected chromosome. Affected fathers can never pass this X-linked disease to their sons but affected fathers can pass the X-linked gene to their daughters who has a 50% chance to pass this disease-causing gene to each of her children. Since females who inherit this gene do not show symptoms, they are called carriers. Each of the female's carrier's son has a 50% chance to display the symptoms but none of the female carrier's daughters would display any symptoms.

Ethical quandaries around expanded carrier screening in third-party reproduction.

Although current screening methods of gamete donors are capable of reducing the incidence of genetic anomalies in donor offspring below general population levels, targeted screening for a large number of conditions (expanded carrier screening or ECS) could be considered as part of the routine selection procedure for gamete donors. There are, however, important drawbacks to its practical implementation. Excluding all carriers of severe recessive monogenic pediatric disorders would disqualify virtually all donors, and other approaches negatively affect cost (and therefore access), present dilemmas in regard to disclosure of genetic findings, and/or overburden the intended parents. In all of the scenarios considered, adequate genetic counseling will be of central importance. Besides looking at benefits and drawbacks of possible ways of implementing ECS, we also examine whether a moral obligation exists to adopt ECS at all and on whose shoulders such an alleged obligation would rest: policymakers, medical staff at fertility clinics, sperm and egg banks, the intended parents? We argue that given the small risk reduction brought about by ECS, the possible negative effects of its implementation, and the absence of widespread preconception carrier screening in the general population, it is inconsistent to argue that there is a moral obligation to perform ECS in the context of donor conception. Finally, implications for the donors are discussed.

Mohr–Tranebjærg syndrome

Genetics This condition is caused by mutations in the TIMM8A gene. This gene is located on the long arm of X chromosome (Xq22). The protein encoded by this gene localizes to the intermembrane space in mitochondria where it functions in the import of nuclear encoded proteins into the mitochondrial inner membrane. How this produces the clinical picture is not yet clear. The pattern of inheritance is X-linked recessive. Where the female is a carrier, male offspring have a 50 percent chance of inheriting the disease and female offspring have a 50 percent chance of being a carrier. Where the male is affected, male offspring do not inherit the pathogenic mutation and females are obligate carriers. TIMM8A is also referred to as DDP. Koehler determined the function of the DDP gene and concluded that the Mohr-Tranebjaerg syndrome is a novel type of mitochondrial disease that is most likely caused by a defective mitochondrial protein-import system. Diagnosis

[Value of chromosome tests in genetic counseling of infertile couples].

A cytogenetic analysis of more than 7000 subjects has been performed in the aetiological screening of infertile couples. This study revealed that infertile couples can be divided into three groups: those with one or more spontaneous abortions before 13 weeks of gestations, those with primary sterility (no gestation for at least 24 months) or those with secondary sterility (after one or more children, no further gestation for at least 24 months). The frequency of chromosomal abnormalities observed in this population is 2,9%, i.e. 1/17 couple. The results, according to sex of subjects bearing the chromosomal abnormality, were then analysed in each of the three groups. From this study, the authors insist on the advantage of systematically performing a chromosome analysis in the case of infertile couples for two main reasons: frequency of chromosomal abnormalities is relatively high in this population, detection of such abnormalities enables some couple to be rapidly directed to other solutions (Artificial Insemination), and others, due to prenatal chromosomal diagnosis, to have offspring in safety.

Attitudes toward fragile X mutation carrier testing from women identified in a general population survey.

Fragile X syndrome is primarily due to a CGG repeat expansion found in the FMR1 X-linked gene. In a previous study, we conducted focus groups with women to assess their attitudes towards fragile X carrier screening. In this follow-up study, we conducted in-depth interviews of general population reproductive-age women who were identified as carriers. We explored their attitudes toward testing for carrier status of the fragile X mutation. These women underwent screening primarily to participate in a research project rather than in search of a diagnosis for specific symptoms. As such, these women were wholly unprepared for positive carrier results. Their responses about their results and carrier screening, in many cases, were being worked out over the course of the interview itself. The most salient finding of this work is the apparent lack of relevance of carrier status to these women. Many expressed that although the information could be relevant in the future, it is not relevant at this stage of their lives in terms of family planning (either with respect to having unaffected offspring or to premature ovarian failure) and personal relationships. Although issues of abortion seemed prominent in the focus groups, we found that carrier status did not have an apparent effect on women's attitudes about termination. We hypothesize this may be related to the fact that women had not processed their new carrier status and had not related it to previously-formed personal opinions. The findings of this work have significant implications for genetic counseling and population screening. Genetic counselors should be mindful that general population women may not recognize the immediate importance of their carrier status even when literature is provided and discussed prior to providing a sample. As part of comprehensive genetic counseling, counselors should identify the reproductive life stage of the woman receiving the new information and help her identify when this information would be more meaningful in her life. Counselors can assist in setting up a personalized road map with specific types of services that will be more applicable to the woman as her carrier status becomes more relevant.

Successful pregnancy after preimplantation genetic diagnosis for carrier of t(2;7)(p11.2;q22) with high rates of unbalanced sperm and embryos: a case report.

Regarding the literature on the results of preimplantation genetic diagnosis (PGD) in reciprocal chromosomal translocation carriers seems to prevail a view that this method reduces the frequency of miscarriages, and the pregnancy rate is directly proportional to the number of normal spermatozoa. Therefore, we compared the results of sperm karyotype analysis of a carrier of familial t(2;7)(p11.2;q22) with PGD results. The carrier was ascertained as his wife had had two miscarriages. Empirical data from a pedigree of t(2;7)(p11.2;q22) carrier was collected. A tri-color fluorescence in situ hybridization method (FISH) was used to show the meiotic segregation pattern in sperm of the proband. PGD of blastomeres from a single ICSI cycle and standard prenatal diagnosis procedures to confirm the PGD results was performed. Meiotic segregation pattern showed only 34.2% of normal/balanced spermatozoa. The high rate (42%) of miscarriages was observed in this family, which could be explained by chromosomal unbalanced karyotypes as a product of fertilization by unbalanced spermatozoa found with a frequency of approximately 66%. The lack of unbalanced progeny at birth suggests a natural selection of unbalanced fetuses. The 37.5% of normal/balanced embryos received after a single ICSI cycle and PGD was similar to the percentage of normal/balanced spermatozoa (34.2%). After 38 weeks a healthy girl with normal karyotype was born. The presented study is an optimistic message for translocation carriers showing that even in case with more than 60% of genetically unbalanced sperm there is a reasonable chance for reproductive success.

What is the threshold of mature oocytes to obtain at least one healthy transferable cleavage-stage embryo after preimplantation genetic testing for fragile X syndrome?

What are the chances of obtaining a healthy transferable cleavage-stage embryo according to the number of mature oocytes in fragile X mental retardation 1 (FMR1)-mutated or premutated females undergoing preimplantation genetic testing (PGT)? In our population, a cycle with seven or more mature oocytes has an 83% chance of obtaining one or more healthy embryos. PGT may be an option to achieve a pregnancy with a healthy baby for FMR1 mutation carriers. In addition, FMR1 premutation is associated with a higher risk of diminished ovarian reserve and premature ovarian failure. The number of metaphase II (MII) oocytes needed to allow the transfer of a healthy embryo following PGT has never been investigated. The study is a monocentric retrospective observational study carried out from January 2006 to January 2020 that is associated with a case-control study and that analyzes 38 FMR1 mutation female carriers who are candidates for PGT; 16 carried the FMR1 premutation and 22 had the full FMR1 mutation. A total of 95 controlled ovarian stimulation (COS) cycles for PGT for fragile X syndrome were analyzed, 49 in premutated patients and 46 in fully mutated women. Only patients aged ≤38 years with anti-Müllerian hormone (AMH) >1 ng/ml and antral follicle count (AFC) >10 follicles were eligible for the PGT procedure. Each COS cycle of the FMR1-PGT group was matched with the COS cycles of partners of males carrying any type of translocation (ratio 1:3). Conditional logistic regression was performed to compare the COS outcomes. We then estimated the number of mature oocytes needed to obtain at least one healthy embryo after PGT using receiver operating characteristic curve analysis. Overall, in the FMR1-PGT group, the median number of retrieved and mature oocytes per cycle was 11 (interquartile range 7-15) and 9 (6-12), respectively. The COS outcomes of FMR1 premutation or full mutation female carriers were not altered compared with the matched COS cycles in partners of males carrying a balanced translocation in their karyotype. Among the 6 (4-10) Day 3 embryos obtained in the FMR1-PGT group, a median number of 3 (1-6) embryos were morphologically eligible for biopsy, leading to 1 (1-3) healthy embryo. A cutoff value of seven MII oocytes yielded a sensitivity of 82% and a specificity of 61% of having at least one healthy embryo, whereas a cutoff value of 10 MII oocytes led to a specificity of 85% and improved positive predictive value. This study is retrospective, analyzing a limited number of cycles. Moreover, the patients who were included in a fresh PGT cycle were selected on ovarian reserve parameters and show high values in ovarian reserve tests. This information could influence our conclusion. The results relate only to the target population of this study, with a correct ovarian reserve of AMH >1 and AFC >10. However, the information provided herein extends knowledge about the current state of COS for FMR1 mutation carriers in order to provide patients with proper counseling regarding the optimal number of oocytes needed to have a chance of transferring an unaffected embryo following PGT. None. N/A.

[Genetic counseling in cases of chromosome insertions].

The principles of the estimation of the risk of repeated birth of malformed child and spontaneous abortion in families of balanced carriers of insertions are presented. A risk for a carrier is formed from two parts: a risk for a carrier of reciprocal translocation and a risk for a carrier of insertion of the came length as inseried segment. The first component of the risk is a constant, the latter one is a variable. It depends on the length of the inserted segment, the type of its inclusion (direct or inverted) and sites of break points. An estimation of the risk in hypothetical insertion 46, XX, inv ins (4; 2) (q24; q22q34) is described as a model. The same method of counselling may be used for the families with triple translocations t(a-, b-, c+) with "insertion" of fragment of chromosome "a" between the parts of "b" and "c" chromosomes. A tentative empirical mean value of repeated birth of malformed child and spontaneous abortion in families with insertions is 29% and 45% for the female carrier, and about 37% and 25% for the male carrier.

Preimplantation genetic diagnosis versus prenatal diagnosis-decision-making among pregnant FMR1 premutation carriers.

To detect which factors influence decision-making among pregnant FMR1 premutation carriers regarding the preferred mode of genetic diagnosis: IVF-PGT-M (in vitro fertilization with preimplantation genetic testing for monogenic gene diseases), or CVS (chorionic villus sampling), or AC (amniocentesis) after spontaneous conception. In Israel FMR1 premutation preconception genetic screening is offered, free of charge, to every woman in her reproductive years. FMR1 premutation carriers with ≥ 70 CGG repeats, or a history of FXS offspring, are offered IVF-PGT-M. This is a historical cohort study including all pregnant FMR1 premutation carriers who underwent prenatal diagnosis between the years 2011 and 2016 at a tertiary medical center. Data were collected from electronic charts and through phone interviews. One hundred seventy-five women with high-risk pregnancies who were offered IVF-PGT-M were evaluated. In 37 pregnancies (21%), the women decided to undergo IVF-PGT-M. Using the generalized estimating equations (GEE) statistical method including seven parameters, we found that previous termination of pregnancy due to FXS and advanced woman's age were significantly associated with making the decision to undergo IVF-PGT-M. Previously failed IVF was the most significant parameter in a woman's decision not to undergo IVF-PGT-M. The most dominant factor affecting the decision of FMR1 premutation carriers to choose spontaneous conception with prenatal diagnosis versus IVF-PGT-M is a previous experience of failed IVF treatments. Women whose IVF treatments failed in the past tended to try to conceive naturally and later, during the course of the pregnancy, perform CVS or AC. Conversely, women who previously experienced a termination of pregnancy (TOP) due to an affected fetus, and older women, preferred to undergo IVF-PGT-M procedures.

Lowe syndrome identified in the offspring of an oocyte donor who was an unknown carrier of a de novo mutation: a case report and review of the literature.

Oculocerebrorenal syndrome of Lowe is an X-linked disorder with very low prevalence in the general population. The OCRL gene encodes the protein phosphatidylinositol 4,5-bisphosphate-5-phosphatase, a lipid phosphatase, located in the trans-Golgi network. Point mutations in the OCRL gene cause Lowe syndrome and Dent disease, which are characterized as a multisystemic disorder. The symptoms of Lowe syndrome are expressed primarily as dysfunction of the eyes, kidneys, and the central nervous system. This report describes a case of a 31-year-old Georgian woman with a de novo pathogenic mutation causing oculocerebrorenal syndrome of Lowe, who was a volunteer in an oocyte donation program for in vitro fertilization purposes, and the outcome of the treatments of this particular donor's oocyte receivers, describing the implications of the mutation for the children born as a result of the treatments. It raises important medical and ethical issues about the necessity of genetic testing of oocyte donors and the possibility of rare genetic disorders being inherited by the offspring of donors. This particular case indicates the legal, medical, and emotional risks of utilizing donor oocytes from phenotypically healthy women, whose genetic constitution is unknown in terms of being silent carriers of rare diseases. In addition, all the necessary actions were followed; the further examinations that are required are mentioned. The donor and the offspring should be further tested. The remaining cryopreserved embryos should be destroyed or preimplantation genetic testing should be performed before they are utilized. Finally, all the people involved, the treated couples and the donor, alongside her family, should follow genetic and psychological counselling.