Ataxia-telangiectasia with hyper-IgM and Wilms tumor: fatal reaction to irradiation.

Ataxia-telangiectasia is an autosomal recessive disorder caused by mutation in the ATM gene. Hallmarks of the disease comprise progressive cerebellar ataxia, oculocutaneous telangiectasiae, cancer susceptibility, and variable humoral and cellular immunodeficiency. We report a patient who, because of the pattern of her immunodeficiency, was primarily diagnosed as an autosomal recessive hyper-IgM syndrome. Only a mild cerebellar ataxia was present at the age of 7 years then she developed a Wilms tumor (nephroblastoma). Conventional radiotherapy for the malignancy led to fatal consequences. Postmortem studies confirmed diagnosis of ataxia-telangiectasia.