Methylmalonic acidemia.

A patient presenting with severe metabolic acidosis accompanied by hyperglycinemia, hyperuricemia, hypoglycemia and hypertammonemia is described. Metabolic acidosis was found to be due to accumulated methylmalonic acid and did not respond to vitamin B12 administration. The patient showed favorable growth and development when kept on a low isoleucine, methionine, threonine and valine diet. In vitro studies using a lymphoid cell line derived from the patient showed a deficiency of methylmalonyl-CoA carbonyl-mutase.