Four novel mutations identified in Norwegian patients result in intermittent maple syrup urine disease when combined with the R301C mutation.

Maple syrup urine disease (MSUD) is caused by a defect in branched chain α-ketoacid dehydrogenase complex (BCKD), an essential metabolon for the catabolism of the branched chain amino acids. Here, we report four novel mutations in the DBT gene, encoding the transacylase subunit (E2) of BCKD, resulting in intermittent MSUD in seven Norwegian patients. The patients had episodes with neurological symptoms including lethargy and/or ataxia during childhood infections.