22q13 deletion

Phelan-McDermid syndrome or 22q13.3 deletion syndrome is a neurodevelopmental disorder caused by deletion of chromosome 22q13.3 or pathogenic variant in SHANK3 gene. Phelan-McDermid syndrome is characterized by global developmental delay, intellectual disability, autism spectrum disorder, hypotonia, seizures, severely delayed or absentspeech, and minor facial anomalies. To date, about 1300 individuals with Phelan-McDermid syndrome are reported worldwide according to Phelan-McDermid Syndrome Foundation. It is believed that the prevalence is considerably greater.