[Autosomal anomalies in a specially selected group of children with mental retardation without signs of Down's syndrome]. / Anomalii autsom v spetsial'no otobrannoi gruppe detei s oligofreniei bez vneshnikh priznakov bolezni Dauna.

Pathogenetic examinations of 96 mentally retarded children with multiple somatic anomalies and developmental defects (but without Down's disease) were carried out. Changes of the caryotype were discovered in 36 children (37.5%). In 21 children (22.0%) there were true autosomal aberrations 1/4 of which were tri- and monosomies, mainly in the form of mosaicism, and 3/4 were non-balanced structural reconstructions of the autosomes. In about 1/3 of the cases the structural anomalies were inherited by the children from their phenotypically healthy parents who had balanced translocations or inversions. In 15 children (15.6%) chromosomal variations were discovered. No differences between the clinical manifestations of the mental retardation in children with true autosomal aberrations and chromosomal variations were noted.

Nature of the longitudinal differential staining of metaphase chromosomes.

Patterns of differential longitudinal spiralization of chromosomes induced by the addition of 5-bromodexyuridine (200 mug/ml) for 5-7 h before fixation of the cells were compared with the differential staining of normally spiralized chromosomes with giemsa stain in chromosomes of lymphocytes in human blood cultures. The patterns of differentiation of both types were found to coincide for all chromosomes of the normal karyotype; areas of incomplete spiralization corresponded to areas staining intensively with giemsa stain. The significance of these results in connection with the mechanisms of differential staining of metaphasechromosomes is discussed.