Radiosensitivity in ataxia-telangiectasia

Abstract

Ataxia-telangiectasia is a syndrome of autosomal recessive inheritance characterized by cerebellar ataxia and oculocutaneous telangiectasia (Boder and Sedgwick, 1958; Karpati et al., 1965). The ataxia, which is progressive, is usually first noticed when the child starts to walk. The telangiectasia, unusual before the age of five, is seen over the bulbar conjunctivae and variously over the ears, nose, cheeks, palate, sternum, antecubital fossae and dorsae of the extremities. Although the basic karyotype is normal there are characteristic chromosomal changes with gaps, breaks, rearrangements, fragments and ring formations (Harnden, 1974). Similar chromosomal instability is also found in Bloom's and Fanconi's syndromes. Immunological deficiency is found in the majority of cases and this may be of either cellular or humoral immunity or both (Peterson, Cooper and Good, 1966). This predisposes to infections especially of the sinobronchial tree. There is also an increased incidence of malignancy, usually of the reticuloendothelial system (Kersey, Spector and Good, 1973). This may be a consequence of the inherent tendency towards cellular mutation in conjunction with the decreased immunological surveillance of immunodeficiency. Each, in other conditions, is associated with an increased incidence of neoplasia. Prognosis is poor because of pulmonary infection and malignancy. Most die in the first decade. Those surviving may develop dementia and chorea. It has been recorded twice before that patients with ataxia-telangiectasia may be sensitive to irradiation (Gotoff, Amirokri and Liebner, 1967; Morgan, Holcomb and Morrissey, 1968).