Deletions of proximal 15q without Prader-Willi syndrome.

Fifteen patients with deletion of proximal 15q without typical Prader-Willi syndrome (PWS) have been reported previously [Schwartz et al, 1985]. We report on 2 additional patients without typical PWS found to have deletions of 15q11-13 on chromosome analysis done for evaluation of developmental delay. Their manifestations include broad nasal bridge with telecanthus, full nasal tip with flare of nasal alae, long upper lip, posteriorly angulated ears, highly arched palate, hypotonia, seizures and marked developmental delay. It was suggested that there may be a specific phenotype associated with this deletion which differs from PWS. Whether this deletion differs from the deletion associated with PWS awaits delineation on a molecular level.