An adult case with cerebellar lesion due to methylmalonic academia combined with hyperhomocysteinemia

An adult man of methylmalonic acidemia combined with hyperhomocysteinemia is reported. He presented with progressive walking instability with mental and behavioral alterations when aged 24 years. Physical examination showed significant cerebellar ataxia and pyramidal signs. Brain magnetic resonance imaging revealed symmetric lesions of bilateral cerebellum. His plasma total homocysteine and urine methylmalonic acid were significantly elevated. Compound heterozygous mutations, c.482G>A and c.217C>T, were found in his MMACHC gene, confirming the diagnosis of cblC deficiency. Improved clinical manifestations and decreased plasma total homocysteine were observed one month after treatment. Key words: Methylmalonic acid; Hyperhomocysteinemia; Cerebellar impairment; MMACHC gene