rs3865444

A SNP in the CD33 gene on chromosome 19. Its most notable genotype is A;A: slight reduction in risk for Alzheimer's disease

Gene
CD33
Location
Chr 1951,224,706 (GRCh38)
Highest magnitude
1.6Minor
Tested on
23andMe, AncestryDNA, FamilyTreeDNA
Minor allele frequency
24%

Genotypes

Plus strand, as in 23andMe and AncestryDNA files.

  1. C;CNot ratedcommon/normalTypical · 0.069% of people
  2. A;CGoodslight reduction in risk for Alzheimer's diseaseMinor · 1.526% of people
  3. A;AMost notableGoodslight reduction in risk for Alzheimer's diseaseMinor · 1.66% of people

SNPedia records rs3865444 on the minus strand: (G;G), (G;T), (T;T). Magnitude rates how notable a genotype is from 0 to 10, not how risky it is.

Frequency

Share of each genotype in 11 HapMap populations.

  • AverageC;C 69% A;C 26% A;A 6%
  • European ancestry (Utah)C;C 50% A;C 37% A;A 13%
  • Han Chinese (Beijing)C;C 68% A;C 28% A;A 4%
  • Japanese (Tokyo)C;C 74% A;C 25% A;A 2%
  • Yoruba (Nigeria)C;C 99% A;C 1% A;A 0%
  • African ancestry (Southwest US)C;C 73% A;C 25% A;A 2%
  • Chinese (Denver)C;C 72% A;C 25% A;A 4%
  • Gujarati IndianC;C 76% A;C 21% A;A 3%
  • Luhya (Kenya)C;C 90% A;C 10% A;A 0%
  • Mexican ancestry (Los Angeles)C;C 23% A;C 47% A;A 30%
  • Maasai (Kenya)C;C 81% A;C 18% A;A <1%
  • TuscanC;C 49% A;C 48% A;A 3%

Conditions, medicines and genes

Notes

From SNPedia

Notes

The less common allele for this SNP, rs3865444(T), is associated with a slight decrease in risk for Alzheimer's disease, on the order of 0.9x (i.e. a 10% decrease in risk). One visualization of such studies is available here on the AlzGene website. Alzheimer's disease associated, based on large 2011 study

A;C

see citations at rs3865444

A;A

see citations at rs3865444

Source and license

Adapted from rs3865444 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 Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice.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.