Smith‐Magenis syndrome (SMS) is a multiple congenital anomaly, mental retardation (MCA/MR) syndrome associated with deletion of chromosome 17 band p11.2. As part of a multi‐disciplinary clinical, cytogenetic, and molecular approach to SMS, detailed clinical studies including radiographic, neurologic, developmental, ophthalmologic, otolaryngologic, and audiologic evaluations were performed on 27 SMS patients. Significant findings include otolaryngologic abnormalities in 94%, eye abnormalities in 85%, sleep abnormalities (especially reduced REM sleep) in 75%, hearing impairment in 68% (approximately 65% conductive and 35% sensorineural), scoliosis in 65%, brain abnormalities (predominantly ventriculomegaly) in 52%, cardiac abnormalities in at least 37%, renal anomalies (especially duplication of the collecting system) in 35%, low thyroxine levels in 29%, low immunoglobulin levels in 23%, and forearm abnormalities in 16%. The measured IQ ranged between 20–78, most patients falling in the moderate range of mental retardation at 40–54, although several patients scored in the mild or borderline range. The frequency of these many abnormalities in SMS suggests that patients should be evaluated thoroughly for associated complications both at the time of diagnosis and at least annually thereafter. © 1996 Wiley‐Liss, Inc.

Williams syndrome is a genetic disorder linked to cognitive and behavioral patterns of varying consistency; this study was conducted to clarify further the strengths and weaknesses of children with Williams syndrome. Fifteen subjects with the characteristic features of Williams syndrome were evaluated using the Stanford-Binet Intelligence Scale for Children, Fourth Edition; the Vineland Adaptive Behavior Scales, Interview Edition; and the Child Behavior Checklist. Cognitive skills ranged from the Moderate Range of Mental Retardation to the Low Average range, with relative strengths in nonverbal and quantitative reasoning. Adaptive skills were delayed, with strengths in communication and socialization. Behaviorally, clinically significant levels of attention problems, borderline-significant levels of social and thought problems, and significantly low levels of social contacts and structured activities were found. In contrast to the findings of many other studies of Williams syndrome, language skills and short-term memory skills were weak. Children with Williams syndrome may present a more evenly developed intellectual profile, with verbal and nonverbal skills being commensurate. In conclusion, a variety of cognitive, adaptive, and behavioral patterns have been shown to be possible in Williams syndrome; therefore, a single predictable cognitive or behavioral phenotype cannot be assumed.

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