What you carry at this position in your DNA and what research says about it.
Lung and Respiratory Health: 8/10 evidence, 24 publications.
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Sample genotype (not yours): C/C
Typical Risk of Lung and Respiratory Diseases
A genetic profile with two copies of the C allele is associated with a baseline risk of developing lung cancer and chronic obstructive pulmonary disease. Daily cigarette consumption also tends to be lower on average compared to those with the T allele.
What this genotype means: Typical risk of lung cancer; Typical risk of COPD; Lower average cigarette consumption.
Sample genotype (not yours): C/T
Increased Risk of Lung and Respiratory Diseases
Presence of one T allele is associated with an elevated risk of developing chronic obstructive pulmonary disease and lung cancer. This genetic variant also correlates with higher nicotine dependence and increased daily cigarette consumption.
What this genotype means: Elevated risk of lung cancer; Elevated risk of COPD; Higher average cigarette consumption.
Sample genotype (not yours): T/T
Elevated Risk of Lung and Respiratory Diseases
Presence of two T alleles is linked to a significantly higher risk of chronic obstructive pulmonary disease and lung cancer. Daily cigarette consumption and nicotine dependence also tend to be strongly elevated with this genetic profile.
Gene function and biological role
Gene Function: The CHRNA3 gene encodes the alpha-3 subunit of the neuronal nicotinic acetylcholine receptor, which forms part of a multi-subunit channel that responds to the neurotransmitter acetylcholine. These receptors are highly expressed in both the central nervous system and peripheral tissues, including the lungs and bronchial epithelial cells. They play a critical role in mediating neurotransmission, regulating cellular responses to nicotine, and modulating inflammatory pathways [1]. Genetic variations within this gene cluster on chromosome 15q25 are heavily implicated in tobacco-related behaviors [2] and susceptibility to respiratory diseases [3].
Variant Impact: The rs12914385 variant is an intron variant located within the CHRNA3 gene on chromosome 15. This genetic change is part of a well-studied gene cluster that influences nicotinic receptor expression and function. Although it does not directly alter the amino acid sequence of the receptor, it is strongly linked to altered expression levels of nicotinic subunits in lung tissue. This variation is associated with differences in nicotine sensitivity, smoking intensity [2], and the risk of developing severe lung conditions [1].
Key Insight: Nicotinic receptors are not just active in the brain; they are also highly active in lung tissue, directly influencing how the lungs respond to smoke and inflammation.
Location: CHRNA3. Chromosome 15 · 15q25.1 · 78.6 Mb
Estimated prevalence by population
Global 48.4%; European 36.9%; African 66.4%; East Asian 52.4%; South Asian 58.0%; Americas 55.1%; Ashkenazi 34.3%; Finnish 43.3%; Middle Eastern 33.8%; Amish 32.6%.
Estimated CC genotype frequency.
Global 41.1%; European 47.7%; African 30.2%; East Asian 40.0%; South Asian 36.3%; Americas 38.2%; Ashkenazi 48.5%; Finnish 45.0%; Middle Eastern 48.7%; Amish 49.0%.
Estimated CT genotype frequency.
Global 10.5%; European 15.4%; African 3.4%; East Asian 7.6%; South Asian 5.7%; Americas 6.6%; Ashkenazi 17.2%; Finnish 11.7%; Middle Eastern 17.5%; Amish 18.4%.
Estimated TT genotype frequency.
Showing effects for C/C genotype
Cancer & Oncology
Lung Cancer
Lung Cancer. Evidence: 8/10. Source: PMID 34290314. Typical Risk.
Organ Systems
Respiratory Health
COPD. Evidence: 10/10. Source: PMID 24621683. Typical Risk.
Chronic Bronchitis. Evidence: 8/10. Source: PMID 25241909. Typical Risk.
Neurology & Mental Health
Addiction & Reward
Cigarettes Per Day. Evidence: 5/10. Source: PMID 33082346. Typical Consumption.
Cardiovascular & Metabolic
Vascular Health & Aneurysm
Peripheral Artery Disease. Evidence: 8/10. Source: PMID 39024449. Typical Risk.
Atherosclerosis. Evidence: 8/10. Source: PMID 39024449. Typical Risk.
Showing effects for C/T genotype
Lung Cancer. Evidence: 8/10. Source: PMID 34290314. ~1.3x Higher Risk.
COPD. Evidence: 10/10. Source: PMID 24621683. ~1.3x Higher Risk.
Chronic Bronchitis. Evidence: 8/10. Source: PMID 25241909. Increased Risk.
Cigarettes Per Day. Evidence: 5/10. Source: PMID 33082346. Higher Consumption.
Peripheral Artery Disease. Evidence: 8/10. Source: PMID 39024449. Increased Risk.
Atherosclerosis. Evidence: 8/10. Source: PMID 39024449. Increased Risk.
Showing effects for T/T genotype
What this genotype means for the people who carry it
Sample genotype: CC (Homozygous)
Nicotinic acetylcholine receptors in the lungs and brain are highly sensitive to environmental exposures like cigarette smoke. Carrying two copies of the C allele at this locus is associated with a typical, baseline risk of developing chronic obstructive pulmonary disease [1]. Large-scale genomic studies have shown that this genetic profile correlates with a lower likelihood of heavy smoking and fewer cigarettes smoked per day [2]. Consequently, the risk of developing lung cancer remains at the standard population baseline rather than being genetically elevated [3]. Furthermore, this genotype is linked to a typical risk of chronic bronchitis and other smoking-related vascular complications like atherosclerosis [4]. Maintaining a smoke-free lifestyle remains the most effective way to protect respiratory health, regardless of genetic predisposition.
Typical risk of lung cancer; Typical risk of COPD; Lower average cigarette consumption.
Sample genotype: CT (Heterozygous)
Nicotinic acetylcholine receptors play a central role in both nicotine addiction pathways and the inflammatory response of lung tissue to smoke. Having one copy of the T allele at this locus is associated with an increased risk of developing chronic obstructive pulmonary disease [1]. This genetic variant is also linked to a higher average number of cigarettes smoked per day, indicating a potential predisposition to stronger nicotine dependence [2]. Because of both direct tissue susceptibility and behavioral tendencies, carriers face an elevated risk of lung cancer [3]. Additionally, this variant is associated with a higher likelihood of chronic bronchitis and vascular issues such as peripheral vascular disease [4]. Avoiding tobacco smoke and minimizing exposure to air pollutants are critical steps for managing these elevated respiratory and cardiovascular risks.
Elevated risk of lung cancer; Elevated risk of COPD; Higher average cigarette consumption.
Sample genotype: TT (Homozygous)
Nicotinic acetylcholine receptors are key mediators of the physiological response to nicotine and are active in bronchial cells. Inheriting two copies of the T allele at this locus is associated with a significantly increased risk of developing chronic obstructive pulmonary disease [1]. This genetic profile is also linked to a higher daily cigarette consumption, suggesting a stronger biological drive toward nicotine dependence [2]. The combination of increased smoke exposure and genetic tissue vulnerability contributes to an elevated risk of lung cancer [3]. Furthermore, this genotype is associated with a higher incidence of chronic bronchitis and vascular complications like atherosclerosis [4]. Given these strong associations, avoiding smoking and secondary smoke exposure is highly beneficial for preserving long-term lung and blood vessel function.
Variants with shared genetic architecture
rs1051730 · CHRNA3 Gene · Chr 15 · Nicotine and Lung Risk
rs8040868 · CHRNA3 Gene · Chr 15 · Lung Health and Smoking Risk
rs8042374 · CHRNA3 Gene · Chr 15 · Lung Cancer Risk
Genetic susceptibility for chronic bronchitis in chronic obstructive pulmonary disease.
Diversity and scale: Genetic architecture of 2068 traits in the VA Million Veteran Program.
Content updated August 2026.
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