rs5443

A SNP in the GNB3 gene on chromosome 12. Its most notable genotype is T;T: viagra is more likely to have an effect. increased metabolic disease risk.

Gene
GNB3
Location
Chr 126,845,711 (GRCh38)
Highest magnitude
2.4Worth knowing
Tested on
23andMe, AncestryDNA, FamilyTreeDNA
Minor allele frequency
48%

Genotypes

As shown in 23andMe and AncestryDNA files.

  1. C;CGoodnormal, but higher risk for several conditionsMinor · 1.529% of people
  2. C;TBadsome riskWorth knowing · 2.141% of people
  3. T;TMost notableBadviagra is more likely to have an effect. increased metabolic disease risk.Worth knowing · 2.430% of people

On SNPedia: (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 4 HapMap populations.

  • AverageC;C 29% C;T 41% T;T 30%
  • European ancestry (Utah)C;C 35% C;T 56% T;T 10%
  • Han Chinese (Beijing)C;C 40% C;T 51% T;T 9%
  • Japanese (Tokyo)C;C 39% C;T 43% T;T 18%
  • Yoruba (Nigeria)C;C 2% C;T 15% T;T 84%

Conditions, medicines and genes

Other GNB3 SNPs

All GNB3 SNPs

Notes

From SNPedia

Show notes, about 460 words

rs5443, a SNP in the G-protein beta3 subunit (GNB3) gene that is more commonly known as the C825T variant, has been linked to a number of metabolic conditions including obesity, coronary artery disease, insulin resistance and therefore diabetes, left ventricular hypertrophy, and hypertension. It has also been linked to how well a patient responds to Viagra (sildenafil). Several studies have been unable to replicate one or more of the associations in at least some populations between this SNP and these conditions. The more notable studies include: *rs5443(T) allele carriers are 2-3 fold more likely to be obese in Caucasian, Chinese, and African American populations. *rs5443(T) carriers are clearly at higher risk for hypertension, but this review indicates that whether they are also at increased risk for stroke and left ventricular hypertrophy remains controversial. *rs5443(T;T) women gain significantly more weight during pregnancy than rs5443(C;T) or rs5443(C;C) women, and had a significantly higher pre-pregnancy body mass index. *rs5443(T;T) genotypes respond to Viagra better. 91% of them have a "positive erectile response" upon taking Viagra, whereas only around 50% of rs5443(C;T) and rs5443(C;C) individuals respond equivalently to the drug. The odds ratio for the positive response was 10.0 (CI: 1.2 - 81.1, p = 0.01). *rs5443(T;T) patients receiving clozapine over a long term for the treatment of schizophrenia gain significantly more weight (16%) compared to patients carrying at least one rs5443(C) allele in a study of Chinese patients. *rs5443(T) carriers taking triptans for the treatment of migraines or cluster headaches were ~3 fold more likely to respond positively compared with rs5443(C;C) homozygotes (OR 2.96, CI:1.34 - 6.56, p=0.0074) in a study of ~200 Caucasian patients. *rs5443(C;T) genotypes are more prevalent in gastroesophageal reflux disease (GERD) patients relative to healthy controls (odds ratio 1.43, CI: 1.04–1.98). *rs5443(C;C) individuals do not lose weight under sibutramine therapy whereas (C;T) and (T;T) individuals do, based on a study of 131 obese Taiwanese patients. 23andMe blog

C;C

ostensibly the 'normal' form, however variation is common, and each genotype seems to show some good and bad consequences.

C;T

linked to a number of metabolic conditions including obesity, coronary artery disease, insulin resistance and therefore diabetes, left ventricular hypertrophy, and hypertension. It has also been linked to how well a patient responds to Viagra (sildenafil).

T;T

linked to a number of metabolic conditions including obesity, coronary artery disease, insulin resistance and therefore diabetes, left ventricular hypertrophy, and hypertension. It has also been linked to how well a patient responds to Viagra (sildenafil).

Source and license

Adapted from rs5443 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.