Basal ganglia lesions in a patient with 3-hydroxyisobutyric aciduria.

3-hydroxyisobutyric aciduria (3HiB-uria) is a very rare organic aciduria that involves valine metabolism. We report the case of a 7-year-old boy with 3HiB-uria who has suffered more than 20 ketoacidotic episodes since the age of 15 months. In the most recent ketoacidotic episode, which was particularly severe, he developed mild dystonia and choreoathetosis. Magnetic resonance imaging (MRI) revealed bilateral swelling and signal abnormalities of the putamina and heads of the caudate nuclei. The abnormal movements showed a gradual improvement over several months, in correlation with neuroradiological findings. 3HiB-uria should be recognized as one of the group of branched chain organic acidemias that can produce lesions in the basal ganglia.