Methylmalonic acidemia (MMA) is a common organic acidemias, mainly due to metabolic deficiencies of the methyl-malonyl coenzyme A mutase or its coenzyme adenosyl cobalamin (vitamin B12). Methylmalonic acidemia can cause a range of clinical manifestations, especially neuropsychiatric symptoms and signs. In this article, we reported one case with bipolar disorder, then diagnosed with methylmalonic acidemia and hyperhomocysteinemia.

To investigate neuropsychiatric symptoms, treatment and efficacy of methylmalonic acidemia and homocysteinemia.

A case of late-onset methylmalonic acidemia and homocysteinemia with psychiatric symptoms was reported. According to the literature, we analyzed the age, sex, neuropsychiatric symptoms and signs, laboratory tests, treatment and efficacy.

There are 15 patients with methylmalonic acidemia and homocysteinemia (including 6 males and 9 females) reported. It was difficult to make diagnosis directly. Cell types were tested in abroad. The clear diagnosis is based on the elevated level of methylmalonic acid. The clinical manifestations of methylmalonic acidemia and homocysteinemia included neurological symptoms and psychiatric symptoms. hydroxocobalamin, cyanocobalamin, methylcobalamin and adenosyl cobalamin were the main treatment drugs.

If it is difficult to explain the neurological symptoms and signs of psychiatric patients, organic or physical disease, such as methylmalonic acidemia with or without homocysteinemia, should be taken into account.