Intellectual developmental disorder with severe speech and ambulation defects

Intellectual developmental disorder with severe speech and ambulation defects (IDDSSAD) is an autosomal dominant neurodevelopmental disorder with onset of features in infancy or early childhood. Affected individuals have global developmental delay with impaired intellectual development and absent speech, and most cannot walk independently. Common dysmorphic features include prominent forehead and wide mouth (summary by Bell et al., 2019).

OMIM