What Is Phelan-McDermid Syndrome?

Looking for Answers
Sarah K. Lee


Phelan-McDermid Syndrome, also known as 22q13 Deletion Syndrome, occurs when genes are missing from the tip of the 22nd chromosome. Children with Phelan-McDermid may have very low muscle tone, delays in motor skills and speech, distinctive facial features, and minor physical abnormalities.

For good basic medical information about Phelan-McDermid Syndrome/22q Deletion Syndrome, visit these pages:

22q Deletion Syndrome
Source: Genetics Home Reference

Phelan-McDermid Syndrome
Source: National Organization for Rare Disorders

22q11.2 Deletion Syndrome Symptoms and Diagnosis
Source: Seattle Children's


For information on Phelan-McDermid Syndrome/22q Deletion Syndrome research, visit these sites:

22q Center on Nationwide Children's

Online Mendelian Inheritance in Man

Phelan-McDermid Syndrome International Registry


National Organization for Rare Disorders

Bearden Lab

These sites offer support to families of children with Phelan-McDermid Syndrome/22q Deletion Syndrome:

Phelan-McDermid Syndrome Foundation

Dempster Family Foundation

Chromosome 22 Central

Rare Chromosome Support Group

Chromosome Disorder Outreach

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