Successful pregnancy in severe methylmalonic acidaemia

Methylmalonic acidaemia is an inborn error of metabolism characterized by recurrent episodes of life‐threatening ketoacidosis. With improved and intensive treatment, these patients are living into adulthood, but many experience late‐onset disease complications such as chronic renal failure, chronic pancreatitis and osteopenia. We report the successful delivery of a healthy baby to a 20‐year‐old woman with vitamin B12‐unresponsive methylmalonic acidaemia who has these late‐onset manifestations of the disease and had plasma methylmalonic acid concentrations of 1900μmol/L during the first trimester of pregnancy.