An unusual balanced reciprocal translocation in several members of a family.

Chromosome abnormalities in structure as well as number have often been found to be associated with congenital anomalies in humans. Numerous genetic mechanisms have been postulated to explain the cytogenetic alterations. Wallace and Anderson (1964) reported a patient with numerous congenital anomalies whose chromosomal analysis revealed 45 chromosomes with a translocation deletion involving members of the D and B Groups. Bray and Ann Josephine (1964) described an infant with severe mental and physical retardation whose karyotype comprised 46 chromosomes with an unusually long B chromosome and suggested that it represented a translocation involving members ofthe B andD groups ofchromosomes. There have been 11 other reports describing long unpaired B group chromosomes without evidence or involvement of the D group chromosomes. We report here results of clinical, biochemical, and cytogenetic studies of a 16-year-old white girl with multiple congenital anomalies and a complex cytogenetic aberration involving chromosomes ofthe B and D groups carried in part by two other phenotypically normal members of her family.