Cytogenetic investigations in a family with ataxia telangiectasia.
Cytogenetic findings on a family with ataxia telangiectasia (A-T) in which three of four sibs were affected are described. The affected individuals had approximately twice the level of spontaneous chromosome breakage of a normal control, while the parents and the normal sib had no significant increase. Lymphocytes from all three A-T homozygotes showed specific stable chromosomal rearrangements involving chromosomes 7 and 14. All of these abnormalities involved breakage at the usual four sites associated with A-T (7p14, 7q35, 14q12, and 14q32). Two rearrangements detected in the eldest and most severely affected patient were clones, one of which [t(14;14)(p11;q12)] is not commonly found in A-T cells. No chromosomal rearrangements were encountered in lymphocytes from the control, the parents, or the normal sib. Lymphocytes from the A-T patients also were found to be 7-11 times more sensitive to the induction of chromatid aberrations by X-irradiation than control cells. Lymphocytes from the parents and normal sib showed a moderately increased frequency of X-ray induced aberrations compared with that of the control.
Department of Medical Genetics, Belfast City Hospital, Northern Ireland.
M W
MW
Humphreys
N C
NC
Nevin
M A
MA
Wooldridge
D001260:Ataxia Telangiectasia / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations; D002883:Chromosomes, Human, Pair 14 / Q000648:ultrastructure; D002897:Chromosomes, Human, Pair 7 / Q000648:ultrastructure; D005260:Female; D006801:Humans; D008214:Lymphocytes / Q000528:radiation effects / Q000648:ultrastructure; D008297:Male; D011836:Radiation Tolerance