[Cytogenic survey of 600 mentally retarded hospitalized patients].

A collaborative study (including the patients of 4 mental hospitals) was done in an attempt to evaluate the incidence of chromosomic anomalies in a large group of mentally retarded patients. A cytogenetic study was performed in 600 mentally retarded patients selected among 3.311 psychiatric patients. Chromosomic anomalies were found in 54 (9 per cent) mentally retarded patients. There were 43 autosomic anomalies (32 had trisomy 21) and 11 sexual chromosomes anomalies. This large series is consistent with the results found in the litterature. However of interest is the fact that this anomalies were frequently associated with affective deprivation, relational distorsion, disturbed family milieu and low social economic status during childhood.