title: Inversion of 'flourescent' segment in chromosome 3: a polymorphic trait.
abstract: The frequency of the 'inversion' of flourescent constitutive heterochromatin in chromosome 3 was the same in a sample of 370 retarded persons as in a sample of 222 mentally normal men. It can be concluded that this 'inversion' is not associated with mental retardation. This variant is more common (4%) in the Canadian population we studied than in samples reported by most other authors (0-1.7%). Possibly the founder effect could play a role in the differences. Two cases of homozygotes for this 'inversion' were identified.
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002871:Chromosome Banding; D007446:Chromosome Inversion; D002900:Chromosomes, Human, 1-3; D005260:Female; D005787:Gene Frequency; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D011796:Quinacrine
chemical_list: D011796:Quinacrine