Rs79761867

rs79761867, formerly known as rs28934895 and more commonly known as R183P, is a mutation (rare SNP) in the branched chain keto acid dehydrogenase E1, beta polypeptide BCKDHB gene. The common allele is rs28934895(G), encoding arginine (R) at amino acid position 183.

With a frequency of about 1 in 100 among Jews of European descent, the much rarer rs28934895(C) allele encodes a proline (P), and it is the most frequent mutation leading to Maple Syrup Urine Disease, accounting for perhaps 90% of the mutations in this population group. However, by itself the mutation does not predict the severity of the disease; note also that only homozygotes (rs28934895(C;C)) are at risk for the disease.

This SNP is often included in screening panels for carriers of deleterious mutations among Ashkenazi Jews, such as carrier screens for prospective parental couples.