title: Distinct chromosome abnormalities in ataxia telangiectasia with chronic T-cell lymphocytic leukemia.
abstract: We report chromosomal studies of a 27-year-old male patient with ataxia telangiectasia who developed a chronic T-cell lymphocytic leukemia. The leukemic cells grew spontaneously although a better yield of metaphases could be obtained after PHA stimulation. Chromosome analysis revealed a hypodiploid leukemic clone (44 chromosomes) and a single remaining normal metaphase. An isochromosome 8q was detected in a subclone at an early analysis, which was lost during clonal evolution. At the time of the last analysis, 6 months before the patient died, the diploid metaphases disappeared completely. The karyotype of the final chromosome study showed a monoclonal condition with the following abnormalities: 44,X,-Y,4q-,6p-,14q-,19p+,20q+,-20,22q-. Loss of the Y chromosome was limited to the leukemic cells. Comparing our data with the chromosome abnormalities reported in the literature, breakpoints at band 14q11-12 (location of the gene for the alpha chain of the T-cell receptor), loss of a normal chromosome #20, as well as structural abnormalities of the remaining chromosome 20p seem to be nonrandom in T-CLL arising in patients with ataxia telangiectasia. A Philadelphia-like marker that seems to be a peculiar feature of the case described here, however, resembles a small marker chromosome qualified as unidentifiable in a similar case of T-CLL reported in the literature.
mesh_terms: D000328:Adult; D001260:Ataxia Telangiectasia / Q000150:complications / Q000235:genetics*; D001853:Bone Marrow / Q000648:ultrastructure; D002869:Chromosome Aberrations; D002871:Chromosome Banding; D005819:Genetic Markers; D006801:Humans; D007621:Karyotyping; D007945:Leukemia, Lymphoid / Q000209:etiology / Q000235:genetics*; D008297:Male; D013601:T-Lymphocytes / Q000648:ultrastructure
chemical_list: D005819:Genetic Markers