Constitutional interstitial deletion of 17(p11.2) (Smith-Magenis syndrome): a clinically recognizable microdeletion syndrome. Report of two cases and review of the literature.

We present two patients, a 12 year old Turkish and a 7 year old Italian girl, with severe mental retardation, multiple congenital malformations and a constitutional interstitial deletion of the short arm of chromosome 17, del(17) (11.2). The main clinical features of this syndrome which is also referred to as the Smith-Magenis syndrome consist of a broad flat midface with brachycephaly, broad nasal bridge, brachydactyly, speech delay, hoarse deep voice and peripheral neuropathy. Behavioural abnormalities include hypermotility, self mutilation and sleep disturbances. The remarkable consistency of the main clinical features of the 59 patients documented so far permits the clinical diagnosis of this syndrome; a fact which is of importance, since many of the reported patients--including ours--were considered normal on earlier cytogenetic studies.