Description of the mutations in 15 subjects with variant forms of maple syrup urine disease.

Background: In maple syrup urine disease (MSUD), disease-causing mutations can affect the BCKDHA, BCKDHB or DBT genes encoding for the E1α, E1β and E2 subunits of the multienzyme branched-chain 2-keto acid dehydrogenase (BCKD) complex.