Various deletions affect the terminal region of the long arm of chromosome 22 (the paternal chromosome in 75% of cases ), from<unk> .3 to 22qter. Although the deletion is most typically a result of a de novo mutation, there is an inherited form resulting from familial chromosomal translocations involving the 22 chromosome. In the de novo form, the size of the terminal deletion is variable and can go from 130 Kb (130,000 base pairs) to 9 Mb. Deletions smaller than 1 Mb are very rare (about 3%). The remaining 97% of terminal deletions impact about 30 to 190 genes (see list, below). At one time it was thought that deletion size was not related to the core clinical features. That observation lead to an emphasis on the SHANK3 gene, which resides close to the terminal end of chromosome 22. Interest in SHANK3 grew as it became associated with autism spectrum disorder (ASD) and Schizophrenia. Since then, twelve other genes on<unk>  (MAPK8IP2, CHKB, SCO2, SBF1, PLXNB2, MAPK12, PANX2, BRD1, CELSR1, WNT7B, TCF20) have been associated with autism spectrum disorder and/or Schizophrenia (see references below). Some mutations of SHANK3 mimic<unk> , but SHANK3 mutations and microdeletions have quite variable impact. Some of the core features of<unk>  are dependent upon deletion size, and do not depend on the loss of SHANK3. As noted above, the distal 1 Mb of 22q is a gene rich region. There are too few clinical cases to statistically measure the relationship between deletion size and phenotype in this region. SHANK3 is also adjacent to a gene cluster (ARSA and MAPK8IP2) that has a high probability of contributing to ASD, suggesting the effects of SHANK3 deletion may be indistinguishable from other genetic losses. A landmark study of induced pluripotent stem cell neurons cultured from patients with<unk>  shows that restoration of the SHANK3 protein produces a significant, but incomplete rescue of membrane receptors, supporting both a substantial role for SHANK3 and an additional role for other genes in the distal 1 Mb of chromosome 22. There is an interest in the impact of MAPK8IP2 (also called IB2) in<unk> . MAPK8IP2 is especially interesting because it regulates the balance between NMDA receptors and AMPA receptors. The genes SULT4A1 and PARVB may cause<unk>  in cases of more proximal interstitial and large terminal deletions. There are about 187 protein coding genes in the<unk>  region. A group of genes (MPPED1, CYB5R3, FBLN1, NUP50, C22ORF9, KIAA1644, PARVB, TRMU, WNT7B and ATXN10), as well as microRNAs may all contribute to loss of language, a feature that varies notably with deletion size. The same study found that macrocephaly seen in<unk>  patients may be associated with WNT7B. FBLN1 is responsible for synpolydactyly as well as its contribution to the neurological manifestations ( OMIM 608180). RABL2B ACR SHANK3 ARSA MAPK8IP2 CHKB CPT1B SYCE3 KLHDC7B ODF3B TYMP SCO2 NCAPH2 LMF2 MIOX ADM2 SBF1 PPP6R2 DENND6B PLXNB2 MAPK11 MAPK12 HDAC10 TUBGCP6 SELO TRABD PANX2 MOV10L1 MLC1 IL17REL PIM3 CRELD2 ALG12 ZBED4 BRD1 FAM19A5 FLJ32756 TBC1D22A CERK GRAMD4 CELSR1 TRMU BC069212 GTSE1 TTC38 PKDREJ CDPF1 PPARA WNT7B ATXN10 FBLN1 RIBC2 SMC1B FAM118A UPK3A KIAA0930 NUP50 PHF21B PRR5-ARHGAP8 LDOC1L KIAA1644 PARVG TRNA_SeC PARVB SAMM50 PNPLA3 PNPLA5 SULT4A1 EFCAB6 MPPED1 SCUBE1 TTLL12 TSPO MCAT BIK TTLL1 PACSIN2 ARFGAP3 A4GALT ATP5L2 DL490307 CYB5R3 RNU12 POLDIP3 SERHL2 RRP7A NFAM1 TCF20 CYP2D6 NDUFA6 SMDT1 FAM109B NAGA WBP2NL CENPM TNFRSF13C SHISA8 SREBF2 CCDC134 MEI1 C22orf46 NHP2L1 XRCC6 DESI1 PMM1 CSDC2 POLR3H ACO2 PHF5A TOB2 TEF ZC3H7B RANGAP1 CHADL L3MBTL2 EP300 RBX1 DNAJB7 XPNPEP3 ST13 SLC25A17 MCHR1 MKL1 SGSM3 ADSL TNRC6B FAM83F GRAP2 ENTHD1 CACNA1I RPS19BP1 ATF4 SMCR7L MGAT3 TAB1 SNORD43 RPL3 PDGFB CBX7 APOBEC3H APOBEC3F APOBEC3D APOBEC3C APOBEC3B CBX6 NPTXR DNAL4 SUN2 GTPBP1 JOSD1 TOMM22 CBY1 FAM227A DMC1 DDX17 KDELR3 KCNJ4 CSNK1E TMEM184B MAFF MAFF PLA2G6 BAIAP2L2 SLC16A8 PICK1 SOX10 POLR2F C22orf23 MICALL1 EIF3L ANKRD54 GALR3 GCAT H1F0 TRIOBP NOL12 LGALS1 SH3BP1 GGA1 LGALS2 CDC42EP1 CARD10 MFNG ELFN2 CYTH4 Table of protein coding genes involved in<unk>  (based on Human Genome Browser – hg38 assembly ). Underline identifies 13 genes that are associated with autism. Bold identifies genes associated with hypotonia (based on Human Phenotype Browser search for 'hypotonia' and the OMIM database ).
22q13 deletion syndrome
13q deletion syndrome
2q37 deletion syndrome
22q11.2 distal deletion syndrome
9q34 deletion syndrome
1q21.1 deletion syndrome
1p36 deletion syndrome
22q11.2 duplication syndrome