chromosome Xp11.22 duplication syndrome
Definition A nonsyndromic X-linked condition (OMIM:300705) characterised by profound mental retardation and impaired adaptive behaviour, which is first seen during early development.
Intellectual deficiency is the only primary symptom of non-syndromic X-linked mental retardation, whilst syndromic mental retardation presents with associated physical, neurological and/or psychiatric manifestations.
Molecular pathology Microduplications of chromosome Xp11.22, a region that includes:
• HSD17B10 (OMIM:300256) which encodes hydroxysteroid dehydrogenase
• HUWE1 (OMIM:300697), which encodes E3 ubiquitin-protein ligase
cause chromosome Xp11.22 duplication syndrome.
Synonym Mental retardation—X-linked 17, mental retardation—X-linked 31