Laboratory testing for prader-willi syndrome

In 1981, Ledbetter and co-workers45 described a cytogenetically visible deletion in proximal 15q in four patients with Prader-Willi syndrome (PWS). Proximal 15q was targeted for analysis because several previously published Prader-Willi cases exhibited an isochromosome 15q or a translocation with proximal 15q breakpoints.12,34 Since the fi rst report of the cytogenetic deletion of proximal 15q in PWS, several cytogenetic and molecular genetic techniques have been used to further characterize the chromosome 15q11-q13 region and for laboratory diagnostic purposes in a range of PWS subjects having a variety of abnormal chromosome fi ndings.