Trisomy 8p: unusual origin detected by fluorescence in situ hybridization.

Chromosomal analysis of a neonate with brain and heart abnormalities revealed trisomy for 8p. The mother's karyotype showed 47 chromosomes with one chromosome 8 being represented as two separate chromosomes, an acrocentric 8p and a telocentric 8q. G-banding and silver staining revealed a satellite and nucleolus organizing region (NOR) on the 8p. Centromeric-specific probes to the centromeres of chromosomes 8, 15, 13/21, 22 and the acrocentric chromosomes revealed that only the 8q centromere was of chromosome-8 origin, while the 8p centromere was of chromosome-14 origin.