Methylmalonic acidemia (MMA) is an autosomal recessive disease of branched chain amino acid metabolism. The disease can be classified as vitamin B12-responsive or nonresponsive type. For the nonresponsive type, there is no curative treatment, and its prognosis is usually poor. We report one case that had vitamin B12-nonresponsive type MMA diagnosed at 3 days of age. The patient received liver transplantation at the age of 11 months. Continuous venovenous hemodialysis was performed immediately pre- and post-transplantation. The attack frequency of metabolic acidosis episodes decreased and the general condition of this patient improved after liver transplantation. So, although not curative, liver transplantation is an effective management for MMA. ; 附設醫院基因醫學部 ; 醫學院附設醫院 ; 期刊論文