BCKDHB
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Gene summaries condense public reference material; disease links and population data change as databases are updated. Clinical decisions belong with your care team.
branched chain keto acid dehydrogenase E1 subunit beta
Normal Function
Health Conditions Related to Genetic Changes
Maple syrup urine disease
More than 90 mutations in the BCKDHB gene have been identified in people with maple syrup urine disease. These mutations most often cause the severe, classic form of the disorder, which becomes apparent soon after birth. Maple syrup urine disease gets its name from the distinctive sweet odor of affected infants' urine. It is also characterized by poor feeding, vomiting, lack of energy (lethargy), abnormal movements, and delayed development.
Most BCKDHB gene mutations change single amino acids in the beta subunit of the BCKD enzyme complex. Other mutations insert or delete small amounts of DNA in the gene. A particular mutation is most common in people of Ashkenazi (eastern and central European) Jewish descent; this mutation replaces the amino acid arginine with the amino acid proline at position 183 in the beta subunit (written as Arg183Pro or R183P).
Mutations in the BCKDHB 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 health problems associated with maple syrup urine disease.
More About This Health ConditionRelated Conditions
Maple syrup urine disease
Health Conditions Related to Genetic Changes
More than 90 mutations in the BCKDHB gene have been identified in people with maple syrup urine disease. These mutations most often cause the severe, classic form of the disorder, which becomes apparent soon after birth. Maple syrup urine disease gets its name from the distinctive sweet odor of affected infants' urine. It is also characterized by poor feeding, vomiting, lack of energy (lethargy), abnormal movements, and delayed development.
Most BCKDHB gene mutations change single amino acids in the beta subunit of the BCKD enzyme complex. Other mutations insert or delete small amounts of DNA in the gene. A particular mutation is most common in people of Ashkenazi (eastern and central European) Jewish descent; this mutation replaces the amino acid arginine with the amino acid proline at position 183 in the beta subunit (written as Arg183Pro or R183P).
Mutations in the BCKDHB 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 health problems associated with maple syrup urine disease.