Cerebellar ataxia with glutamic aciduria

We report a case of cystinuria and glutamic aciduria, presenting with progressive cerebellar manifestations. She had cerebellar type dysarthria and limb ataxia. Head MRI revealed cerebellar atrophy. Urinary amino acid analysis showed excessive excretion of glutamate and the dibasic amino acids (cystine, arginine, lysine, and ornithine). Cystine and glutamic acid are thought to be transported in a common membrane transport system. Reduction of glutamic acid and cystine in the cerebrospinal fluid was revealed. A relationship between cystinuria and cerebellar manifestation was discussed.