rs3818361

A SNP in the CR1 gene on chromosome 1. Its most notable genotype is A;A: 1.2x increased risk for late-onset Alzheimer's

Gene
CR1
Location
Chr 1207,611,623 (GRCh38)
Highest magnitude
1.2Minor
Tested on
23andMe, AncestryDNA, FamilyTreeDNA
Minor allele frequency
27%

Genotypes

Plus strand, as in 23andMe and AncestryDNA files.

  1. G;GNot ratednormalTypical · 0.050% of people
  2. A;GBad1.15x increased risk for late-onset Alzheimer'sMinor · 1.140% of people
  3. A;AMost notableBad1.2x increased risk for late-onset Alzheimer'sMinor · 1.210% of people

SNPedia records rs3818361 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.

Frequency

Share of each genotype in 11 HapMap populations.

  • AverageG;G 50% A;G 40% A;A 10%
  • European ancestry (Utah)G;G 58% A;G 32% A;A 10%
  • Han Chinese (Beijing)G;G 42% A;G 45% A;A 12%
  • Japanese (Tokyo)G;G 50% A;G 38% A;A 12%
  • Yoruba (Nigeria)G;G 30% A;G 48% A;A 22%
  • African ancestry (Southwest US)G;G 28% A;G 54% A;A 18%
  • Chinese (Denver)G;G 44% A;G 42% A;A 14%
  • Gujarati IndianG;G 89% A;G 10% A;A 1%
  • Luhya (Kenya)G;G 32% A;G 62% A;A 6%
  • Mexican ancestry (Los Angeles)G;G 76% A;G 24% A;A 0%
  • Maasai (Kenya)G;G 37% A;G 48% A;A 15%
  • TuscanG;G 63% A;G 33% A;A 4%

Conditions, medicines and genes

Other CR1 SNPs

All CR1 SNPs

Notes

From SNPedia

Notes

rs3818361 is a SNP associated with the complement component (3b/4b) receptor 1 CR1 gene. The association of this SNP and late-onset Alzheimer's disease was replicated over a total of another 1829 cases (and 2576 controls). The odds ratio for rs3818361(T) allele was 1.15 (note the p value was 0.014).

Source and license

Adapted from rs3818361 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 Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice.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.