rs28934895

A SNP in the BCKDHB gene on chromosome 6. Its most notable genotype is C;C: Maple syrup urine disease

Gene
BCKDHB
Location
Chr 680,168,945 (GRCh38)
Highest magnitude
5.0Very important
Tested on
Not on consumer chips

Genotypes

As shown in 23andMe and AncestryDNA files.

  1. C;CMost notableBadMaple syrup urine diseaseVery important · 5.0
  2. C;GNot ratedcarrier for Maple Syrup Urine diseaseWorth knowing · 2.5
  3. G;GNot ratednormalTypical · 0.0

On SNPedia: (C;C), (C;G), (G;G). Magnitude rates how notable a genotype is from 0 to 10, not how risky it is.

Conditions, medicines and genes

Other BCKDHB SNPs

All BCKDHB SNPs

Genosets

Genosets combine several genotypes. Twofold checks them in your report.

Notes

From SNPedia

Show notes, about 150 words

rs28934895, also 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. Note also that 23andMe uses a different name for this SNP; in their terminology, rs28934895 is called i3002808.

Source and license

Adapted from rs28934895 on SNPedia, using a snapshot taken October 16, 2026. SNPedia content is shared under CC BY-NC-SA 3.0 US, and this page is shared under the same license.

SNPedia is a community-edited wiki. Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice. Magnitude is a community rating of how interesting a genotype is, not a risk score.