DBT and phenylketonuria: The first is a novel stop mutation in the gene DBT, encoding the Dihydrolipoyl transacylase subunit (E2) of Branched-chain alpha-keto acid dehydrogenase complex, one of the genes causing maple syrup urine disease (OMIM 248600); the second is a known mutation in Phenylalanine hydroxylase (PAH) [34], the gene mutated in phenylketonuria (OMIM 261600).