Ataxia telangiectasia: a model for T-cell leukemogenesis.

Ataxia telangiectasia is a complex genetic disease which includes a high risk to develop lymphoid malignancies. In approximately 10% of the patients, clonal translocations are observed in large T lymphocytes populations, with generally no consequences for the patient. Cytological and biological studies of these cell populations have shown striking similarities with T-cell prolymphocytic leukemia. Clonal chromosomal aberrations are constituted by the translocation of one TCR gene to either the 14q32.1 band or the Xq28 band. Whereas no gene candidate is yet identified on the 14q32.1 region, we have recently identified a new gene on Xq28 that may play a role in leukemogenesis.