A chromosome survey of a hospital for the mentally subnormal

Abstract

A cytogenetic survey of 756 resident, but otherwise unselected, mentally retarded patients in a Scottish [UK] hospital is reported. The karyotypes of all patients were examined using orcein-stained cells; abnormal ones other than those with standard trisomy 21, were further investigated using a banding technique. A total of 103 patients had abnormal chromosome complements of whom 91 had Down''s syndrome (including 6 with translocations), 6 had some other autosomal abnormality and 6 had an abnormality of the sex chromosome complement, including 2 with an XXYY complement. Details of the clinical and cytogenetic features are presented.