rs121964972
A SNP in the CBS gene on chromosome 21. Its most notable genotype is A;A: homocystinuria which is unresponsive to vitamin B6
- Gene
- CBS
- Location
- Chr 2143,060,528 (GRCh38)
- Highest magnitude
- 4.5Very important
- Tested on
- AncestryDNA
Genotypes
Plus strand, as in 23andMe and AncestryDNA files.
- G;GGoodcommon in clinvar
- A;GBadcarrier for homocystinuria which is unresponsive to vitamin B6
- A;AMost notableBadhomocystinuria which is unresponsive to vitamin B6
SNPedia records rs121964972 on the minus strand: (C;C), (C;T), (T;T). Magnitude rates how notable a genotype is from 0 to 10, not how risky it is.
Related
Other CBS SNPs
- rs5742905G;Gpossible miscall in Ancestry V2.0 datasets; otherwise, Mild clinical homocystinuria which is responsive to vitamin B6Important
- rs121964962C;TCarrier of a homocystinuria mutationImportant
- rs121964963A;GCarrier of a homocystinuria mutationImportant
- rs121964965C;TCarrier of a homocystinuria mutationImportant
- rs121964967C;TCarrier of a homocystinuria mutationImportant
- rs375846341G;TCarrier of a homocystinuria mutationImportant
- rs398123151A;GCarrier of a homocystinuria mutationImportant
- rs751464024C;TCarrier of a homocystinuria mutationImportant
Notes
From SNPedia
Notes
307S (common in Irish populations) is associated with a more severe form of Homocystinuria and is unresponsive to pyridoxine (vitamin B6) treatment.
Source and license
Adapted from rs121964972 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 Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice.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.