rs733618

A SNP in the CTLA4 gene on chromosome 2. Its most notable genotype is C;T: 1.87x risk for myasthenia gravis

Gene
CTLA4
Location
Chr 2203,866,221 (GRCh38)
Highest magnitude
1.8Minor
Tested on
23andMe, AncestryDNA, FamilyTreeDNA
Minor allele frequency
17%

Genotypes

Plus strand, as in 23andMe and AncestryDNA files.

  1. T;TNot ratednormalTypical · 0.068% of people
  2. C;TMost notableBad1.87x risk for myasthenia gravisMinor · 1.826% of people
  3. C;CNot ratednormalTypical · 0.06% of people
  4. A;ANot ratedNo summary available.Typical · 0.00% of people

SNPedia records rs733618 on the minus strand: (A;A), (A;G), (G;G), (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.

  • AverageT;T 68% C;T 26% C;C 6% A;A 0%
  • European ancestry (Utah)T;T 89% C;T 9% C;C 2% A;A 0%
  • Han Chinese (Beijing)T;T 39% C;T 45% C;C 16% A;A 0%
  • Japanese (Tokyo)T;T 36% C;T 48% C;C 16% A;A 0%
  • Yoruba (Nigeria)T;T 73% C;T 25% C;C 2% A;A 0%
  • African ancestry (Southwest US)T;T 79% C;T 16% C;C 5% A;A 0%
  • Chinese (Denver)T;T 38% C;T 47% C;C 16% A;A 0%
  • Gujarati IndianT;T 78% C;T 21% C;C 1% A;A 0%
  • Luhya (Kenya)T;T 69% C;T 27% C;C 4% A;A 0%
  • Mexican ancestry (Los Angeles)T;T 86% C;T 14% C;C 0% A;A 0%
  • Maasai (Kenya)T;T 68% C;T 28% C;C 5% A;A 0%
  • TuscanT;T 92% C;T 8% C;C 0% A;A 0%

Conditions, medicines and genes

Other CTLA4 SNPs

All CTLA4 SNPs

Notes

From SNPedia

Notes

rs733618, also known as T/C-1772, 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 rs733618(A;G) heterozygotes had an odds ratio of 1.87 (CI: 1.01-3.49, p=0.049) for the disease compared to healthy individuals, yet neither allele on its own showed increased risk. rs231775 (CTLA4_+49_G/A P=0.0219) and rs733618 (CTLA4_-1722_T/C P=0.0096) susceptibility to Graves' disease

Source and license

Adapted from rs733618 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 Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice.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.