TRISOMY-13 MOSAICISM DEMONSTRATED ONLY IN SKIN FIBROBLASTS IN A PATIENT PRESENTING PSYCHOMOTOR RETARDATION, PIGMENTARY DYSPLASIA AND SOME DYSMORPHIC FEATURES

A Brazilian female infant presented delayed psychomotor development, s kin pigmentary dysplasia and some dysmorphic features. Chromosome anal ysis from peripheral blood culture was normal, but the karyotype from skin fibroblasts revealed mosaicism for trisomy 13. This case demonstr ates the relevance of performing chromosomal analysis of skin fibrobla sts in patients with mental retardation, associated with pigmentary dy splasia of the skin and a normal karyotype in peripheral blood lymphoc ytes. To our knowledge, it is the first report of trisomy 13 demonstra ted only in skin fibroblasts.