To test the hypothesis that iron is increased in the cerebellum of patients with Friedreich’s ataxia (FA), a multigradient echo magnetic resonance sequence for the three-dimensional imaging of brain iron-induced contrast was used in 12 patients and 23 normal subjects examined at the National Institutes of Health, Bethesda, MD. Relaxation rate (R2) values, the inverse of T2, in the unaffected globus pallidus were equal in FA patients and controls, but R2 values in the dentate nucleus of FA patients were significantly higher. These R2 values reflect an increased iron concentration in the dentate, which supports the hypothesis of oxidative damage as the mechanism for FA. 
COMMENT. Increased iron in the dentate nucleus of patients with Friedreich’s ataxia, demonstrated by magnetic resonance, points to oxidative damage as the pathogenesis.