Clinical, Molecular, and Cytogenetic Survey of Potential Prader-Willi Syndrome Patients

Abstract

The association of an interstitial deletion of chromosome 15q11–13 with the Prader-Willi Syndrome (PWS) has been known since 1981 (Ledbetter et al, 1981 and 1982). However, about 37% of patients are cytogenetically normal (Ledbetter et al, 1987). The discovery of maternal heterodisomy for 15q11–13 in two patients with PWS (Nicholls et al, 1989) raised the question of whether such a phenomenon could explain many or even all non-deletion patients. To answer such a question requires a very good clinical diagnosis and reliable molecular data, and was the major impetus for the work presented here.