Prenatal diagnosis of ataxia telangiectasia

INCREASED SPONTANEOUS CHROMOSOME BREAKAGE rates in peripheral blood lymphocytes and cultured skin fibroblasts is characteristic of ataxia telangiectasia. 1 Recently, we have shown the presence of a clastogenic factor, a low molecular weight peptide, in plasma of patients with AT and in conditioned medium from their cultured skin flbroblasts2 ~ Normal human lymphocytes cultured in AT fibr0blast conditioned medium or in plasma from AT patients show an increased chromosome breakage rate (0.10 breaks per cell) as compared to controls (0.00 to 0.03 breaks per cell). In this report we describe the prenatal diagnosis of a fetus at risk for AT, based on the presence of the clastogenic factor in the amniotic fluid, as well as on spontaneous chromosome breakage and a chromosomal translocation involving chromosome 14 in the cultured amniotic fluid cells. The diagnosis has been confirmed by an increased spontaneous chromosome breakage rate in the fetal amniotic membrane cells.