rs4553808

A SNP in the CTLA4 gene on chromosome 2. Its most notable genotype is A;A: normal

Gene
CTLA4
Location
Chr 2203,866,282 (GRCh38)
Highest magnitude
0.0Typical
Tested on
23andMe, AncestryDNA
Minor allele frequency
15%

Genotypes

As shown in 23andMe and AncestryDNA files.

  1. A;AMost notableNot ratednormalTypical · 0.085% of people
  2. A;GNot ratedpossibly lower risk for myasthenia gravisTypical · 0.014% of people
  3. G;GNot rated0.05x (decreased) risk for myasthenia gravisTypical · 0.0<1% 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 3 HapMap populations.

  • AverageA;A 85% A;G 14% G;G <1%
  • European ancestry (Utah)A;A 79% A;G 19% G;G 2%
  • Han Chinese (Beijing)A;A 85% A;G 15% G;G 0%
  • Japanese (Tokyo)A;A 92% A;G 8% G;G 0%

Conditions, medicines and genes

Other CTLA4 SNPs

All CTLA4 SNPs

Notes

From SNPedia

Notes

rs4553808, also known as A/G-1661, is a SNP in the upstream activator sequence of the cytotoxic T lymphocyte associated antigen-4 CTLA4 gene. This gene encodes the CD152 antigen. A study of 165 Swedish myasthenia gravis patients concluded that the rs4553808(G;G) homozygotes had an odds ratio of 0.05 (CI: 0.00286-0.874, p=0.0023) for the disease compared to healthy individuals, while the rs4553808(G) allele showed a less dramatic reduction in risk, with an odds ratio of 0.578 (CI: 0.373-0.897, p=0.015).

Source and license

Adapted from rs4553808 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 Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice.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.