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Phelan-McDermid Syndrome

Phelan-McDermid syndrome, also known as 22q13.3 deletion syndrome, is a condition caused by the loss of a small piece of chromosome 22.

The deletion occurs near the end of the chromosome at a location designated q13.3. The features of 22q13.3 deletion syndrome vary widely and involve many parts of the body.

Characteristic signs and symptoms include developmental delay, moderate to profound intellectual disability, decreased muscle tone (hypotonia), and absent or delayed speech.

Some people with this condition have autism or autistic-like behavior that affects communication and social interaction, such as poor eye contact, sensitivity to touch, and aggressive behaviors.

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