No abstract

A pericentric inversion has been discovered in one branch of a family, in which a 21/22 translocation of the usual type had been transmitted through three generations. The female carrier of the translocation with inversion appears to be phenotypically normal. She has, however, an obvious tendency to develop aneuploid offspring.

No 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.

No abstract