[Genetic mental retardation in the district of Banská Bystrica].

The authors investigated the prevalence of mental retardation (MR) in 6-14-year-old children in the district of Banská Bystrica. The aim was to assess the prevalence of MR and the ratio and character of genetic factors participation in its genesis. The group was based on the Uniform records of defective children and health records of children from special schools and social care institutes in 1987. From a total of 23,510 children 510 (2.16%) suffered from MR. In the population of gipsy children the authors found 21.5% with MR, while in the population of non-gipsy children the percentage was 0.9%. Genetic examinations were made in 106 children with MR. In 33 of these (31.1%) there was evidence of a genetic aetiology (monogenic disease in 21, chromosomal aberration in 11 and in one instance polyfactorial disease); a non-genetic aetiology was found in 21 children (19.8%). The aetiology was not elucidated in 52 children (49.0%). The authors emphasize the importance of genetic prevention for reducing the number of children with MR but draw attention also to non-medical factors which may play a part in the aetiology of mental retardation in a part of the child population.