rs33930165
A SNP in the HBB gene on chromosome 11. Its most notable genotype is T;T: 93% reduction in malarial risk
- Gene
- HBB
- Location
- Chr 115,227,003 (GRCh38)
- Highest magnitude
- 0.0Typical
- Tested on
- 23andMe, AncestryDNA
- Minor allele frequency
- <1%
Genotypes
Plus strand, as in 23andMe and AncestryDNA files.
- T;TMost notableNot rated93% reduction in malarial risk
- G;TNot rated29% reduction in malarial risk
- G;GNot ratedvariant
- C;CGoodcommon in clinvar
SNPedia records rs33930165 on the minus strand: (A;A), (A;C), (C;C), (G;G). Magnitude rates how notable a genotype is from 0 to 10, not how risky it is.
Related
Other HBB SNPs
- rs11549407A;ABeta Thalassemia major; Hemoglobin beta-zeroVery important
- rs33945777T;TBeta Thalassemia major; Hemoglobin beta-zero; possibly transfusion dependentVery important
- rs33960103G;GBeta Thalassemia major; Hemoglobin beta-zero; possibly transfusion dependentVery important
- rs33971440T;TBeta Thalassemia major; Hemoglobin beta-zero; possibly transfusion dependentVery important
- rs33974936T;TBeta Thalassemia major; Hemoglobin beta-zeroVery important
- rs33986703A;ABeta Thalassemia major; Hemoglobin beta-zero; possibly transfusion dependentVery important
- rs34716011T;TBeta Thalassemia major; Hemoglobin beta-zero; possibly transfusion dependentVery important
- rs34889882-;-Beta Thalassemia major; Hemoglobin beta-zero; possibly transfusion dependentVery important
Notes
From SNPedia
Notes
rs33930165 is a relatively rare SNP found in the beta hemoglobin HBB gene, adjacent to the well-known SNP associated with malarial resistance (rs334). This SNP gives rise to the "Hb C", or hemoglobin C, form of hemoglobin as the HBB forms are commonly named. It is found primarily in a subset of West Africa. rs33930165 is associated with increased malarial resistance, yet without giving rise to sickle cell anemia. A study of 4,000+ individuals in Burkina Faso found that rs33930165(A;G) heterozygotes had a 29% reduction in risk of clinical malaria (p = 0.0008), and rs33930165(C;C) homozygotes had a 93% reduction (p = 0.0011).
G;G
this geno is very prone to notational confusion. good test case.
Source and license
Adapted from rs33930165 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 Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice.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.