The Cohen syndrome.

A 9.5-year old severely mentally retarded boy is reported with the typical features of the Cohen syndrome. It is emphasized that this syndrome be differentiated from other constitutional syndromes featuring mental retardation, obesity short stature and hypotonia, because of a different genetic prognosis. Compared to the Prader-Labhart-Willi syndrome the craniofacial appearance of this autosomal recessively inherited malformation syndrome is characterised by antimongoloid position of the eyes, dental anomalies with prominent upper incisors and malocclusion, and high-arched palate. Ocular anomalies mostly include pigmentary retinal anomalies. Whereas hypotonia is severe from the beginning, obesity becomes only striking after the age of 5 years.