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Reviewed December 2008

What is the official name of the BCKDHA gene?

The official name of this gene is “branched chain keto acid dehydrogenase E1, alpha polypeptide.”

BCKDHA is the gene's official symbol. The BCKDHA gene is also known by other names, listed below.

Read more about gene names and symbols on the About page.

What is the normal function of the BCKDHA gene?

The BCKDHA gene provides instructions for making one part, the alpha subunit, of an enzyme complex (a group of enzymes that work together). This complex is called branched-chain alpha-keto acid dehydrogenase, or BCKD. Two alpha subunits connect with two beta subunits, which are produced from the BCKDHB gene, to form a critical part of the enzyme complex called the E1 component.

The BCKD enzyme complex is responsible for one step in the normal breakdown of three protein building blocks (amino acids). These amino acids—leucine, isoleucine, and valine—are obtained from the diet. They are present in many kinds of food, particularly protein-rich foods such as milk, meat, and eggs. The BCKD enzyme complex is active in mitochondria, which are specialized structures inside cells that serve as energy-producing centers. The breakdown of leucine, isoleucine, and valine produces molecules that can be used for energy.

How are changes in the BCKDHA gene related to health conditions?

maple syrup urine disease - caused by mutations in the BCKDHA gene

More than 40 mutations in the BCKDHA gene have been identified in people with maple syrup urine disease, most often in individuals with the severe, classic form of the disorder. Most BCKDHA mutations change single amino acids in the alpha subunit of the BCKD enzyme complex. In the Old Order Mennonite population, where maple syrup urine disease occurs frequently, the most common mutation replaces the amino acid tyrosine with the amino acid asparagine at position 438 (written as Tyr438Asn or Y438N).

Mutations in the BCKDHA gene disrupt the normal function of the BCKD enzyme complex, preventing it from effectively breaking down leucine, isoleucine, and valine. As a result, these amino acids and their byproducts build up in the body. This accumulation is toxic to cells and tissues, particularly in the nervous system. The buildup of these substances can lead to seizures, developmental delay, and the other medical problems associated with maple syrup urine disease.

Where is the BCKDHA gene located?

Cytogenetic Location: 19q13.1-q13.2

Molecular Location on chromosome 19: base pairs 41,397,789 to 41,425,005

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBIThis link leads to a site outside Genetics Home Reference.)

The BCKDHA gene is located on the long (q) arm of chromosome 19 between positions 13.1 and 13.2.

The BCKDHA gene is located on the long (q) arm of chromosome 19 between positions 13.1 and 13.2.

More precisely, the BCKDHA gene is located from base pair 41,397,789 to base pair 41,425,005 on chromosome 19.

See How do geneticists indicate the location of a gene? in the Handbook.

Where can I find additional information about BCKDHA?

You and your healthcare professional may find the following resources about BCKDHA helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the BCKDHA gene or gene products?

  • BCKDH E1-alpha
  • branched chain keto acid dehydrogenase E1, alpha polypeptide (maple syrup urine disease)
  • MSUD1

Where can I find general information about genes?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

What glossary definitions help with understanding BCKDHA?

acids ; amino acid ; asparagine ; breakdown ; dehydrogenase ; developmental delay ; enzyme ; gene ; isoleucine ; leucine ; mitochondria ; mutation ; nervous system ; population ; protein ; subunit ; toxic ; tyrosine ; valine

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

See also Understanding Medical Terminology.

References (6 links)


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.

Reviewed: December 2008
Published: February 8, 2016