About Phelan-McDermid Syndrome
Phelan-McDermid syndrome is caused by deletion of 22q13.3 or point mutations in SHANK3, encoding a scaffolding protein at glutamatergic synapses critical for synapse formation and plasticity. Clinical features include severe intellectual disability, absent or severely delayed speech, global developmental delay, neonatal hypotonia, autism spectrum features, minor dysmorphic features, and absent or minimal pain perception. Insulin-like growth factor 1 (IGF-1) and intranasal insulin have been studied as potential treatments.
Common Clinical Features
Clinical Trial Eligibility Tips
What to know before applying to Phelan-McDermid Syndrome trials.
22q13.3 deletion size or specific SHANK3 variant must be documented — deletion size correlates with phenotype severity and affects trial eligibility
Autism diagnostic measures (ADOS-2, ADI-R) are standard baseline tools alongside adaptive behavior scales
IGF-1 and insulin trials require baseline metabolic and IGF-1 level documentation
Regression episodes (loss of previously acquired skills, often with fever) should be tracked and documented — regression history affects eligibility
Patient Resources
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