rs5443

rs5443 is a SNP in the HTR2A (GNB3) gene. It is associated with a number of metabolic conditions like obesity, diabetes, coronary heart diseases etc.

Mechanism

This SNP codes for GNB3, which in turn codes for a second messenger complex associated with 5HT2A receptor signaling (R).
The T allele is thought to increase secondary messenger signaling (R).

Better response to viagra, more likely to be obese, hypertension, SSRI-induced sexual dysfunction, respond to triptans for migraines (TT). T allele carriers are 2-3 fold more likely to be obese in Caucasian, Chinese, and African American populations (R).
Higher risk for hypertension (R).
Significant weight gain during pregnancy (TT vs CT or CC). Women had a significantly higher pre-pregnancy body mass index (R).
Better response to Viagra (TT). 91% of them have a "positive erectile response" upon taking Viagra, whereas only around 50% of CT and CC individuals respond equivalently to the drug (OR=10, p = 0.01) (R).
Significant weight gain while taking anti-depressants. Patients with TT receiving clozapine over a long term for the treatment of schizophrenia gain significantly more weight (16%) compared to patients carrying at least one C allele in a study of Chinese patients (R).
Better response to Triptans. T carriers taking triptans for the treatment of migraines or cluster headaches were ~3 fold more likely to respond positively compared with CC (OR 2.96, p=0.0074) in a study of ~200 Caucasian patients (R).
Positively associated with endurance athletes [R]

GERD. CT genotypes are more prevalent in gastroesophageal reflux disease (GERD) patients relative to healthy controls (OR 1.43) (R).
An inability to lose weight with the drug sibutramine. CC individuals do not lose weight under sibutramine (weight loss drug) therapy whereas CT and TT individuals do according to a study of 131 obese Taiwanese patients (R).