label: Phelan-McDermid syndrome
label_lc: phelan-mcdermid syndrome
description: "A rare genetic neurodevelopmental disorder characterized by neonatal hypotonia, global developmental delay, normal to accelerated growth, absent to severely delayed speech, and minor dysmorphic features. Phelan-McDermid syndrome can be caused by a deletion at chromosome 22q13 or by mutation in the SHANK3 gene."