Late-onset ataxia telangiectasia

Ataxia telangiectasia (AT) is a rare autosomal-recessive disorder caused by mutations in the AT-mutated (ATM) gene (chromosome 11q 22-23) with absent or aberrant ATM protein kinase.¹ It is usually characterized by childhood-onset cerebellar ataxia, oculocutaneous telangiectasia, oculomotor apraxia, immunodeficiency, increased malignancy risk, and early mortality (classical AT).¹ Recently it has become apparent that a spectrum of milder adult-onset phenotypes exist (variant AT), associated with residual expression of functional ATM protein.^2,3 These patients demonstrate a predominance of extrapyramidal features, later age at ataxia onset, slower progression, and an extended lifespan. We report the case of a woman first diagnosed with AT at the unusually late age of 60.