title: [Polymorphism of the heterochromatic regions of chromosomes 1, 9, 16 and Y and mental retardation].
abstract: Polymorphism of the heterochromatic regions (HR) on chromosomes 1, 9, 16 and in three groups of boys at the age of 3 to 14 years was studied. Two groups of boys with olygophrenia of unknown etiology differed by the extent of mental defect, the latter being debility in 50 children, while other 50 children had the profound mental defect. The control group consisted of 50 healthy children. The chromosome sets of all 150 children were normal. The comparative analysis of chromosome polymorphism of C-segments did not reveal any difference between the controls and the children with a slight degree of mental defect. The children with profound mental defect had reduced lengths and variability of C-segments on the chromosomes studied. The problem of relationship between the criteria of patients selection and the results of the study are discussed. The expedience of further investigation of HR polymorphism in patogenetically homogenous groups of children with mental defect is emphasized.
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002871:Chromosome Banding; D002900:Chromosomes, Human, 1-3 / Q000648:ultrastructure*; D002902:Chromosomes, Human, 16-18 / Q000648:ultrastructure*; D002906:Chromosomes, Human, 6-12 and X / Q000648:ultrastructure*; D014644:Genetic Variation; D006570:Heterochromatin / Q000235:genetics*; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics*; D008297:Male; D011110:Polymorphism, Genetic; D014998:Y Chromosome / Q000648:ultrastructure*
chemical_list: D006570:Heterochromatin
vernacular_title: Polimorfizm geterokhromaticheskikh raĭonov khromosom 1, 9, 16 i Y i umstvennaia otsatlost'.