Phelan-McDermid Syndrome

PMS is a rare genetic condition caused by a deletion on the terminal end of chromosome 22. It is also referred to 22q13. Common symptoms include arachnoid cyst, dilation of cerebral ventricles, aspiration, autism or autistic-like behavior, gastrointestinal issues, severe developmental delays, gross motor delays, severe intellectual disability, inability to sweat, hypotonia, lymphedema recurrent otitis media, seizures, speech delays/absent speech, subluxation of the hip, vesicoureteral reflux, and ptosis/strabismus. There is no cure or treatment specifically for PMS.


Nervous, Digestive, Circulatory. Lymphatic, Renal, Endocrine, Exocrine, and Muscular systems can be affected.

Intellectual Disability

The majority of people with PMS have significant learning challenges and will never live independently.

Mobility and Feeding

Low muscle tone, swallowing, and GI issues make moving and eating challenging.


Many people with PMS are non-verbal communicators.


25-50% of PMS individuals have seizures.


It is estimated that PMS diagnoses are 1% of autism population.