A rare genetic X-linked syndromic intellectual disability disorder with characteristics of moderate to severe intellectual disability associated with epilepsy, short stature, autistic features and behavioral problems, such as self- injury and aggressive outbursts. Observed facial dysmorphism includes brachycephaly, prominent supraorbital ridges, and deep-set eyes. Additional variable manifestations include malposition of feet, asthenic habitus, hyporeflexia, bowel occlusions, hydronephrosis, horseshoe kidney, delayed motor development and disturbed sleep-wake cycle. Caused by mutation in the GRIA3 gene. [from SNOMEDCT_US]