Mount Sinai study finds Phelan-McDermid syndrome prevalence much higher than previously thought

A new study published in the journal Autism Research indicates that Phelan-McDermid syndrome (PMS) is significantly more common than previously estimated. Researchers at the Seaver Autism Center at Mount Sinai found the prevalence to be approximately 1 in 7,300 people, a substantial increase from prior estimates of 1 in 30,000 to 1 in 50,000.

The analysis was based on data from nearly 180,000 individuals with autism, utilizing ten different sources including GeneDx, Labcorp, Ambry Genetics, and the Autism Sequencing Consortium. The findings suggest a prevalence of 13.7 cases per 100,000 people, which could mean over 45,000 people in the United States are living with the condition.

Phelan-McDermid syndrome is a genetic disorder caused by a mutation or deletion of the SHANK3 gene on chromosome 22. It is associated with developmental delays, intellectual disabilities, and speech issues, and is believed to account for up to 1% of all autism spectrum disorder cases. Researchers noted that the gap between known and estimated cases is likely due to structural barriers and a lack of widespread genetic testing for individuals with developmental disabilities.