Mosaic trisomy 15 in a short girl with hemihypotrophy and mental retardation.

We describe a girl with short stature, mild mental retardation, hemihypotrophy, atrial septal defect I, bilateral branchial cleft fistulas and abnormal skin pigmentation. Growth hormone deficiency and other frequent causes of short stature were excluded. Blood karyotype was investigated twice. In one sample an additional marker chromosome was found in one of 53 analysed metaphases, which could not be further characterized, whereas a second investigation showed a normal female karyotype. Cytogenetic studies in skin fibroblasts revealed a mosaic trisomy 15. Although mosaic trisomy 15 is a rare finding the diagnosis must be considered in the presence of pigmentary changes, body asymmetry, short stature and other minor dysmorphic signs even if blood karyotype is normal.