With few exceptions (e.g., Lesch-Nyhan syndrome), the specific nature of self-injury in relation to identified genetic syndromes associated with mental retardation is poorly understood. In the present study we surveyed the families of 62 persons with Prader-Willi syndrome to determine the prevalence, topographies, and specific body locations of self-injurious behavior. Self-injury was reported for 81% of the participants. Skin-picking was the most prevalent form, with the front of the legs and head being disproportionately targeted as preferred self-injury body sites. Individuals with the 15q11-q13 deletion injured significantly more body sites than did individuals with maternal disomy 15. Results are discussed in relation to previous self-injury body site findings and implications for the relevance of syndrome-specific behavioral phenotypes.Prader-Willi syndrome, first described by Prader, Labhart, and Willi (1956), is caused by a deletion in the 15q11-q13 region of chromosome 15 and is associated with infantile hypotonia, hyperphagia, hypogonadism, food-seeking and perseveration, marked obesity, and mild to moderate mental retardation (Butler, Meaney, & Palmer, 1986;Butler, Levine, Le, Hall, & Cassidy, 1995;Dykens, Hodapp, Walsh, & Nash, 1992). The majority of Prader-Willi syndrome cases are caused by a paternal deletion of chromosome 15, but approximately one third of individuals have a maternal disomy 15, in which case both chromosome 15s come from the mother. Although Prader-Willi syndrome is known best for its association with food foraging, hoarding, and morbid obesity, a number of other significant aberrant behaviors are common among children and adults with Prader-Willi syndrome, including temper tantrums, emotional dysregulation, mood lability, anxiety, obsessions and compulsions, and self-injurious behavior-SIB Dykens, Hodapp, Walsh, & Nash, 1997). Self-injurious behavior among persons with mental retardation, autism, and related developmental disabilities ranges from 5% to 60%, depending on the methods used and the populations sampled. Current prevalence estimates for adults with mental retardation suggest that approximately 1 person in 5 living in a residential treatment facility engages in some form of self-injury (Thompson & Gray, 1994). Serious health problems are posed by persistent self-injury, including blindness associated with eye-poking, subdural hemorrhage from forceful head-banging, infections from self-inflicted skin-picking, and anorectal disease resulting from rectal picking and digging (Bhargava, Putnam, Kocoshis, Rowe, & Hanchett, 1996;Hellings & Warnock, 1994). Self-injurious behaviors are among the most clinically problematic behavioral consequences associated with Prader-Willi syndrome. In previous studies, investigators reported SIB (most notably skin-picking) to be a prevalent behavioral problem for 69% of a sample of adolescents with Prader-Willi syndrome (Whitman & Accardo, 1987) and in 81% of a sample of adults with Prader-Willi syndrome (Thornton & Dawson, 1990).
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