rs6656401

A SNP in the CR1 gene on chromosome 1. Its most notable genotype is A;A: 1.18x increased risk for late-onset Alzheimer’s

Gene
CR1
Location
Chr 1207,518,704 (GRCh38)
Highest magnitude
1.5Minor
Tested on
23andMe, AncestryDNA
Minor allele frequency
9%

Genotypes

As shown in 23andMe and AncestryDNA files.

  1. A;AMost notableBad1.18x increased risk for late-onset Alzheimer’sMinor · 1.51% of people
  2. A;GBad1.18x increased risk for late-onset Alzheimer’sMinor · 1.514% of people
  3. G;GGoodcommon/normalTypical · 0.084% of people

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

Frequency

Share of each genotype in 9 HapMap populations.

  • AverageA;A 1% A;G 14% G;G 84%
  • European ancestry (Utah)A;A 9% A;G 30% G;G 61%
  • Han Chinese (Beijing)A;A 0% A;G 7% G;G 93%
  • Japanese (Tokyo)A;A 0% A;G 5% G;G 95%
  • Yoruba (Nigeria)A;A 0% A;G 3% G;G 97%
  • Chinese (Denver)A;A 0% A;G 5% G;G 95%
  • Gujarati IndianA;A 1% A;G 10% G;G 89%
  • Luhya (Kenya)A;A 0% A;G 12% G;G 88%
  • Mexican ancestry (Los Angeles)A;A 0% A;G 22% G;G 78%
  • TuscanA;A 3% A;G 33% G;G 64%

Conditions, medicines and genes

Other CR1 SNPs

All CR1 SNPs

Notes

From SNPedia

Show notes, about 170 words

A 2015 analysis 24 studies totaling 30,000 late-onset Alzheimer's disease patients reported a slight but statistically robust association with the rs6656401(A) minor allele; the odds ratio was 1.18 (CI: 1.15-1.22, p = 1.82e-26). Genetic variations in the CLU and PICALM genes are associated with cognitive function in the oldest old. Fine mapping of genetic variants in BIN1, CLU, CR1 and PICALM for association with cerebrospinal fluid biomarkers for Alzheimer's disease. PICALM and CR1 variants are not associated with sporadic Alzheimer's disease in Chinese patients. CR1 is associated with amyloid plaque burden and age-related cognitive decline. CR1 genotype is associated with entorhinal cortex volume in young healthy adults. Polymorphisms of CR1, CLU and PICALM confer susceptibility of Alzheimer's disease in a southern Chinese population. Alzheimer's disease risk factor complement receptor 1 is associated with depression. A coding variant in CR1 interacts with APOE-epsilon4 to influence cognitive decline.

Source and license

Adapted from rs6656401 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.