DLD-deficiency is a genetic disorder meaning that mutations occur in the DLD gene encoding an enzyme called dihydrolipoamide dehydrogenase (LADH, E3). As a consequence, LADH variants with altered biochemical properties (stability, functionality, tendency to interact with other enzymes in our cells) are expressed impairing cellular metabolism and energy production. LADH operates as a common component of multienzyme complexes (pyruvate dehydrogenase, α-ketoglutarate dehydrogenase, branched-chain α-keto acid dehydrogenase, α-ketoadipate dehydrogenase complexes, and the glycine cleavage system) that are all affected but to different degrees in DLD-deficiency.