A cytogenetic survey of an institution for the mentally retarded: I. Chromosome abnormalities

Abstract
A cytogenetic survey of 475 patients in an institution for the mentally retarded is reported. The chromosomes of all patients were studied using both a non-banding and a G[Giemsa]-banding technique in order to estimate the relative efficiency of the 2 techniques in detecting structural rearrangements of the chromosomes. A total of 57 patients had a chromosome abnormality, including 5 with a balanced structural rearrangement. The contribution of chromosome aberrations to the etiology of mental retardation is discussed with special emphasis on the contribution of balanced structural rearrangements.