CHRNA3 encodes the nicotinic acetylcholine receptor alpha 3 subunit. The encoded protein is a ligand-gated ion channel that likely plays a role in neurotransmission and release of neurotransmitters after exposure to a stimulant such as with nicotine intake.
Polymorphisms in this gene have been associated with an increased risk of smoking initiation and an increased susceptibility to lung cancer. If you carry this genetic variation, it advisable to avoid smoking and second-degree smoking.
The GG genotype is associated with normal receptor function.