NIH CONFERENCE Ataxia-Telangiectasia: A Multisystem Hereditary Disease with Immunodeficiency, Impaired Organ Maturation, X-Ray Hypersensitivity, and a High

Ataxia-telangiectasia is an autosomal, recessive, multisystem disorder characterized by cerebellar ataxia, oculocutaneous telangiectasia, recurrent sinopulmonary infections, high incidence of neoplasia, and variable immunodeficiency. Synthesis of antibodies and certain immunoglobulin subclasses is disrupted, due to disorders of B-cell and helper-T-cell function. Patients have various disorders of cell-mediated immunity, including an inability to produce antigen-specific cytotoxic lymphocytes to viral pathogens. Ataxia-telangiectasia is associated with disorders of cell growth and chromosomal integrity as well as an increased sensitivity to certain chemical and physical agents, including ionizing irradiation, and potential abnormalities in DNA repair mechanisms. Patients have an embryonic-appearing thymus and persistent production of alpha-fetoprotein—features suggesting a generalized disorder of tissue differentiation