[5] BCKDHA is a coding gene that is part of the BCKD complex (branched-chain alpha-keto acid dehydrogenase).

After he had seen a family with four children die only a few months after birth, he found that their urine smelled sweet like maple syrup.

[supplied by OMIM][5] The normal function of the BCKDHA gene is to provide instructions for making the alpha subunit of the branched-chain alpha-keto dehydrogenase (BCKD) enzyme complex.

[6] Earlier cases of this disease show the mutation more frequently occurred by replacing the amino acid tyrosine.

When these byproducts start to accumulate it produces a toxic environment for cells and tissues, specifically in the nervous system.

The BCKDHA has been pinpointed in people with maple syrup urine disease, due to over 80 mutations occurring in that gene.

In terms of maple syrup urine disease, the enzyme defect occurs in the metabolic pathway of the “branched-chain amino acids” leucine, isoleucine, and valine.

There are five forms of maple syrup urine disease: classic, intermediate, intermittent, thiamine-responsive and E3 deficient.

The form of disease is dependent upon clinical prognosis, dietary protein tolerance, and thiamine response and level of enzyme activity.