Duplication in the proximal portion of the long arm of chromosome 15, in a girl without phenotypic features of the Prader-Willi syndrome.

The present report concerns a mentally retarded 14-year-old girl with epilepsy. Her karyotype showed a duplication in the proximal portion of the long arm of chromosome 15. Deficiency as well as excess of chromosome 15 material is sometimes associated with Prader-Willi Syndrome. On clinical investigation no symptoms of this syndrome were found in our patient. The abnormal chromosome appeared to have a duplication for the bands q 14 and q 15.