Alex Kolevzon, MD, Professor of Psychiatry and Pediatrics at the Icahn School of Medicine at Mount Sinai, explains the pathophysiology of Phelan-McDermid syndrome and how it is current treated.

Phelan-McDermid syndrome is genetic disorder and one of few known monogenic causes of autism. It is estimated to occur in approximately 1% of individuals with autism and 2% of those with both autism and intellectual disability. 

Phelan-McDermid syndrome is a caused by deletions or mutations of the SHANK3gene. Persons with this rare disease experience significant intellectual disability and are monitored for management of multiple devastating developmental and medical conditions, which can include epilepsy, mood disorders, hypotonia, sleep disturbances, regressions or failure to retain skills, gastrointestinal dysfunction, fine and gross motor deficits, and severe expressive and receptive language deficits.

There are currently no approved treatments for Phelan-McDermid syndrome. Dr. Kolevzon notes that psychopharmaceutical agents are commonly used for these patients but clinicians need to be aware that some patients will not respond to those therapies and as predicted.

On November 8th, Phelan-McDermid syndrome families will participate in a Externally-Led  Patient-Focused Drug Development (EL-PFDD) meeting to educate the US Food and Drug Administration (FDA) about the Phelan-McDermid syndrome and the need to accelerate the development of treatment options for this disease and other disorders related to the SHANK family of genes.

For additional information about the meeting, visit

To learn more about Phelan-McDermid syndrome and other genetic diseases, visit