Analysis estimates Phelan-McDermid syndrome prevalence at 1 in 7,300

Researchers led by the Seaver Autism Center at Mount Sinai analyzed genetic testing data from nearly 180,000 people with autism to estimate the prevalence of Phelan-McDermid syndrome. The disorder involves deletions or mutations affecting SHANK3 on chromosome 22 and is associated with developmental, medical, and behavioral challenges. The study, published in Autism Research, combined ten sources, including diagnostic laboratories, autism research programs, and academic medical centers.

After adjusting for undiagnosed cases, testing limitations, and affected individuals without autism, researchers estimated a population prevalence of 13.7 per 100,000, or approximately 1 in 7,300. Applied to the United States, this suggests more than 45,000 affected individuals. Researchers attributed the gap between known and estimated cases partly to limited access to genetic testing, insurance barriers, and tests that inadequately assess SHANK3.

A genetic diagnosis may facilitate specialized care and participation in clinical trials, but the source provides no treatment efficacy results. The prevalence figure is an adjusted estimate derived from autism testing datasets rather than direct population screening; the report does not provide uncertainty intervals or detailed adjustment methods. This account is based on CureSHANK-provided material, and the study received support from CureSHANK and Neuren Pharmaceuticals. Reviewing the original paper is warranted before interpreting the estimate as established population prevalence.