<unk> , also known as Phelan–McDermid syndrome (PMS), is a genetic disorder caused by deletions or rearrangements on the q terminal end (long arm) of chromosome 22. Any abnormal genetic variation in the q13 region that presents with significant manifestations (phenotype) typical of a terminal deletion may be diagnosed as<unk> . There is disagreement among researchers as to the exact definition of<unk> . The Developmental Synaptopathies Consortium defines PMS as being caused by SHANK3 mutations, a definition that appears to exclude terminal deletions. The requirement to include SHANK3 in the definition is supported by many but not by those who first described<unk> . Prototypical terminal deletion of<unk>  can be uncovered by karyotype analysis, but many terminal and interstitial deletions are too small. The availability of DNA microarray technology for revealing multiple genetic problems simultaneously has been the diagnostic tool of choice. The falling cost for the whole exome sequencing and, eventually, whole genome sequencing, may replace DNA microarray technology for candidate evaluation. However, fluorescence in situ hybridization (FISH) tests remain valuable for diagnosing cases of mosaicism (mosaic genetics) and chromosomal rearrangements (e.g., ring chromosome, unbalanced chromosomal translocation). Although early researchers sought a monogenic (single gene genetic disorder) explanation, recent studies have not supported that hypothesis (see Etiology).
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