Obsessive-Compulsive Symptoms in Prader-Willi and “Prader-Willi—Like” Patients

OBJECTIVE: To compare obsessive-compulsive (OC) symptoms in patients with Prader-Willi syndrome (PWS) and symptoms in a group of patients presenting with "Prader-Willi-like" features but without the genetic abnormalities associated with PWS. METHOD: 16 patients aged 4 through 20 years were evaluated in a clinic specializing in the assessment and management of behavioral and food-related problems in PWS. Eight patients were found to have key features of the syndrome but did not have a PWS genotype. These PWS-like subjects were matched to 8 clinic patients with a confirmed deletion of the PWS critical region of the paternally derived chromosome 15. All subjects were evaluated for obesity, IQ, food-related problems, maladaptive behaviors, and non-food-related OC symptoms. RESULTS: There were no differences between the 2 groups with respect to measures of obesity, IQ, food-related difficulties, or overall maladaptive behaviors. The PWS group showed significantly greater numbers of OC symptoms and greater symptom severity. CONCLUSIONS: Patients with PWS have elevated numbers of OC symptoms and significant symptom-related impairment which are not explained by developmental delay, food-related difficulties, or obesity. OC symptoms are part of a behavioral phenotype that accompanies deletions on the proximal long arm of chromosome 15 in PWS.