Behavior phenotype in the RSH/Smith-Lemli-Opitz syndrome.

The behavior phenotype of Smith-Lemli-Opitz syndrome (SLOS) was studied by assessing behavior, social, and communication abilities, sensory hyperreactivity, and the deficits associated with autistic disorder. Fifty-six SLOS subjects, age 0.3 to 32.3 years, were evaluated by multiple age-dependent questionnaires and telephone interviews. Of the 56 subjects, 50 (89%) had a history of repeated self-injury: 30 (54%) bit themselves; 27 (48%) head-banged; and 30 (54%) threw themselves backward in a highly characteristic upper body movement ("opisthokinesis"). Forty-seven of these subjects were also evaluated by direct observation and by direct interview of the parent or caregiver. Of 11 subjects 10 years or older, three (27%) had a stereotypic stretching motion of the upper body accompanied by hand flicking. Additional measures showed sensory hyperreactivity, temperament dysregulation, sleep disturbance, and social and communication deficits. Nine of 17 subjects (53%) met the diagnostic criteria for autistic disorder by the Autism Diagnostic Interview-Revised (ADI-R) algorithm questions [Lord et al., 1993, 1994]. Thus, SLOS is a metabolic disorder that can be associated with autism and other behavioral characteristics that define a distinctive and diagnostically important behavioral disorder.