[Non random position of metaphasic chromosomes. IV. Study of translocations t(7;14)(p14;q12) and t(7;14)(q35;q12)].

A study is reported on the distances between rearranged chromosomes and between their normal homologues in the case of t(7;14)(p14;q12) and of t(7;14)(q35;q12), in lymphocytes from patients with ataxia-telangiectasia (AT) and in non-affected persons. The study shows that rearranged chromosomes, in t(7;14)(p14;q12) are closer together, in non-AT persons, than their normal homologues. This is interpreted as the result of recent, repeated, and poorly transmitted mutations, in non-AT persons. On the contrary, this translocation, probably not eliminated in AT patients, becomes the most frequent.