Cerebral microbleeds and iron depletion of dentate nuclei in ataxia-telangiectasia

A 27-year-old man had been diagnosed with ataxia-telangiectasia at age 13 years. He had ocular telangiectasia and motor ataxia, with incoordination of head and eyes in lateral gaze. Laboratory data revealed deficiency of immunoglobulin and elevated α-fetoprotein. MRI demonstrated cerebellar atrophy and cerebral microbleeds1 (figure 1); the dentate nuclei had deficient iron signals, which otherwise should be visible as hypointensities in susceptibility-weighted imaging (figure 2). Iron depletion in dentate nuclei is a novel finding and could be explained by the blockage of axonal iron transport in the olivocerebello-olivary loop.2