Molecular cytogenetic parameters in fibroblasts of ataxia telangiectasia carrier.

Ataxia telangiectasia (AT) is a pleiotropic and rare (1:40,000 to 1:100,000) recessive disease. Laboratory investigations have failed to detect any consistent anomaly in cells from AT heterozygotes. To estimate random aneuploidy, we applied a fluorescence in situ hybridization technique with alpha-satellite probes for chromosomes 8 and 9 and replication pattern for RB-1, HER-2/neu, and the imprinted SNRPN loci on primary AT carrier fibroblasts. Higher random aneuploidy was not found in the carrier fibroblasts compared to control amniocytic cells. The asynchrony pattern was higher in the AT carrier cells with the RB-1 locus (P=0.057) and significantly higher with the HER-2/neu locus (P < 0.001) compared to control cells. As for the imprinted locus SNRPN, there was a significantly lower asynchrony rate in the AT carriers (P < 10(-5)) compared to the control group. Molecular cytogenetic parameters of random aneuploidy and replication pattern may reflect predisposition for the development of cancer. It is possible that in some AT carriers the genetic instability phenomena associated with the abnormal replication pattern may represent their potential for developing malignancies.