[Vitamin-B12-dependent methylmalonic acidemia in twins].

The tendency towards metabolic acidosis developing during simple infections lead to the detection of hyperglycinemia which was shown to be caused by the rare inborn error of metabolism, which was shown to be a methylmalonic acidemia, in identical twins. Under a protein restricted diet and vitamin-B12-injections once a week, all clinical symptoms disappeared so that vitamin-B12-dependency became evident. Under this therapeutic regimen methylmalonic aciduria was well under control.