Phelan-McDermid syndrome is a neurodevelopmental disorder caused by the terminal deletion of chromosome 22 (22q13) followed by the loss of function of the SHANK3 gene. Various terminal deletions of chromosome 22q13 are associated with Phelan-McDermid with a spectrum of phenotypic severity. Here, we have done a clinical molecular study of a Chinese proband with Phelan-McDermid syndrome. Both the proband and her younger brother are associated with this syndrome while their parents are phenotypically normal. We used a karyotype in order to detect the genotype of the proband and her younger brother. We have also used whole genome low-coverage paired-end next generation sequencing to determine whether the parent is the carrier of translocation with terminal 22q13 deletions. We found that both proband and her younger brother are comprises of a novel deletion of 22q13.31q13.33, harboring genes were associated with several clinical phenotype such as severity of speech delay, neonatal hypotonia, delayed in age of walking, male genital anomalies, dysplastic toenails, large and fleshy hands, macrocephaly, short stature, facial asymmetry, and atypical reflexes. Probands and her younger brother inherited this translocation from their mother whereas their father is genotypically normal. In conclusion, our present study expands the deletion spectrum and report a novel deletion associated with Phelan-McDermid syndrome.
Keywords: 22q13 deletion syndrome; Phelan–McDermid syndrome; SHANK3; novel deletion; translocation.