Ataxia-telangiectasia. X,14 translocation, progressive deterioration of lymphocyte numbers and function, and abnormal in vitro immunoglobulin production.

Three children with ataxia-telangiectasia have been followed up since their early childhood. Sequential immunological, biochemical and chromosome studies have been performed over the last 7 years. All the children showed progressive cerebellar ataxia and inexorable neurological deterioration. Further evidence for the progressive nature of this condition is the fall in lymphocyte counts, deterioration of lymphocyte transformation responses to mitogens, and an increase in chromosomal translocations and breakage. Elevated serum alpha-fetoprotein levels are a highly characteristic and useful diagnostic finding in this condition. Two of the patients had an X,14 translocation. In vitro studies of immunoglobulin synthesis suggest an intrinsic defect in B-cell synthesis as well as decreased helper T-cell activity. In spite of moderately severe and progressive abnormalities in the immune system, sinopulmonary infections have not been prominent in our patients.