Emphysema Risk and Your Genetics

By the ExomeDNA Research Team | Last reviewed May 29, 2026

This page contains general information only. For personal health decisions, consult a qualified clinician.

Emphysema Risk is the inherited component of susceptibility to emphysema, a progressive condition in which the tiny air sacs (alveoli) in the lungs are destroyed, reducing the surface area available for gas exchange and causing breathlessness, reduced exercise capacity, and declining lung function. Genome-wide association studies conducted in large, multi-ancestry cohorts have identified specific variants in genes such as SERPINA1, CHRNA5, SERPINA2, and MFSD9 that contribute meaningfully to an individual's risk profile. Below: what the science shows, what these genes do in your lungs, and what steps matter most.

What is emphysema?

Emphysema is a form of chronic obstructive pulmonary disease (COPD) defined by the irreversible destruction of alveolar walls. Healthy lungs contain roughly 300 million alveoli — tiny elastic air sacs that collectively provide a gas-exchange surface roughly the size of a tennis court. In emphysema, the walls between alveoli break down, merging small sacs into larger, less elastic spaces. The result is a lung that cannot efficiently extract oxygen from each breath or expel carbon dioxide.

The hallmark measurement is a reduced FEV1/FVC ratio on spirometry — the ratio of how much air a person can forcibly exhale in one second (FEV1) to their total forced vital capacity (FVC). A ratio below 0.70 after bronchodilator treatment confirms airflow obstruction. In more advanced emphysema, chest X-ray and CT scanning reveal characteristic hyperinflation, flattened diaphragm, and increased lung lucency from destroyed tissue.

Symptoms develop gradually: initially breathlessness only on exertion, progressing to breathlessness at rest, chronic cough, weight loss, and barrel chest. Because emphysema shares the COPD umbrella with chronic bronchitis, patients often have features of both.

Crucially, emphysema is not inevitable even in genetically susceptible individuals — the trigger is almost always an environmental exposure. Cigarette smoke accounts for roughly 90% of cases. Other contributing exposures include occupational dust and fumes (coal dust, grain dust, silica, cadmium), air pollution, and recurrent respiratory infections. Genetics determines how susceptible the lungs are to damage from those exposures, not whether damage occurs in the absence of exposure.

The genetics behind emphysema risk

Four authorized genes carry the GWAS signal for emphysema PheCode 496.1 based on multi-ancestry data from the VA Million Veteran Program (Verma et al. 2024, PMID 39024449):

SERPINA1 holds the strongest genetic association with emphysema of any known gene, with an Open Targets Locus-to-Gene (L2G) score of 0.96, the highest confidence tier. SERPINA1 encodes serine protease inhibitor A1, better known as alpha-1 antitrypsin (AAT). AAT is produced primarily in the liver, secreted into the bloodstream, and reaches the lung where it performs a critical function: it inhibits neutrophil elastase, a proteolytic enzyme that, left unchecked, digests elastin in alveolar walls.

The protease-antiprotease balance is the core mechanism of emphysema pathogenesis. Neutrophils recruited to the lung during smoking-related inflammation release elastase as part of their normal defensive activity. In individuals with sufficient functional AAT, elastase activity is rapidly neutralized. In individuals with reduced or dysfunctional AAT, the balance tilts toward destruction of lung tissue. The Z allele of SERPINA1 (Glu342Lys substitution, rs28929474) causes AAT to misfold and polymerize within the liver rather than being secreted, dramatically reducing circulating AAT levels. Homozygous ZZ individuals have AAT levels roughly 10-15% of normal. Alpha-1 antitrypsin deficiency (AATD) affects approximately 1 in 2,500-5,000 people of Northern European ancestry and is substantially under-detected, often labeled as COPD or asthma for years before AATD-specific testing is performed.

ClinVar records 45 pathogenic and 29 likely pathogenic SERPINA1 variants associated with conditions including AATD — the highest burden of pathogenic lung-related variants of any gene in this trait's genetic architecture.

CHRNA5 encodes the alpha-5 subunit of neuronal nicotinic acetylcholine receptors (nAChRs) and sits in the 15q25.1 chromosomal region, one of the most replicated loci in GWAS studies of smoking behavior and lung disease. This gene carries an L2G score of 0.77 for emphysema. The rs16969968 variant in CHRNA5 illustrates a dual genetic burden: it simultaneously makes nicotine more rewarding in the brain's reward circuitry (increasing nicotine dependence and making cessation harder) and increases lung tissue susceptibility to smoke-induced damage. This means carriers of the high-risk variant face a compounded challenge — a genetic pull toward continued smoking and a genetic vulnerability in the lung responding to that smoke. This is not a moral judgment on willpower; it is a biological mechanism documented in multiple GWAS cohorts.

SERPINA2 is located immediately adjacent to SERPINA1 in the serpin gene cluster at chromosome 14q32. It encodes a protein structurally similar to AAT and participates in the same antiprotease cluster that protects lung tissue from protease-driven degradation. Its precise contribution to emphysema pathobiology is an active area of investigation, and its role in the lung antiprotease defense system is being further characterized.

MFSD9 encodes Major Facilitator Superfamily Domain Containing 9, a predicted transmembrane transporter. Its specific mechanistic role in emphysema biology is still being characterized, and it represents a signal identified through large-scale GWAS that awaits functional follow-up.

What the research says

Research base: Robust.

The primary study grounding this trait is Verma A et al. (2024), published as PMID 39024449. This genome-wide association study examined 2,068 traits across participants in the VA Million Veteran Program (MVP), one of the largest and most ancestry-diverse biobank studies in the world. The scale of the study — hundreds of thousands of veterans with linked electronic health records — provided statistical power to identify genetic associations across a broad range of clinical phenotypes, including emphysema defined by PheCode 496.1 (ICD-10 J43/J43.9).

Key evidence from the research base:

• SERPINA1 achieves the highest L2G confidence score (0.96) of any gene in this trait's architecture, triangulated via protein quantitative trait locus (pQTL) colocalization alongside genomic distance evidence — multiple independent lines of genetic evidence converging on the same gene.
• CHRNA5 registers an L2G score of 0.77 at chromosome 15q25.1, consistent with prior GWAS studies of COPD and smoking phenotypes in UK Biobank and other large cohorts. The 15q25.1 locus has been independently replicated in multiple ancestries.
• The four authorized genes — SERPINA1, CHRNA5, SERPINA2, MFSD9 — represent protein-coding, biologically plausible candidates from credible GWAS loci with high-confidence mapping scores.

The VA MVP dataset's multi-ancestry design is a particular strength: prior GWAS for emphysema and COPD were heavily weighted toward European-ancestry participants. The MVP's broader ancestry composition strengthens the generalizability of identified loci.

Emphysema GWAS findings from UK Biobank, SPIROMICS, and COPDGene cohorts corroborate the CHRNA5 and SERPINA1 loci identified here.

How emphysema affects you

Emphysema affects nearly every system involved in physical function and quality of life:

Breathing mechanics. Destroyed alveolar walls lose their elastic recoil. Air traps in the lung after each breath, leading to hyperinflation, barrel chest, and diaphragm flattening. Each subsequent breath requires more muscular effort.

Gas exchange. Reduced alveolar surface area means each breath delivers less oxygen to the blood and removes less carbon dioxide. Resting oxygen saturation may remain normal for years but falls with exertion first, then eventually at rest in advanced disease.

Exercise capacity. The combination of air trapping, reduced oxygen delivery, and hyperinflation severely limits exercise tolerance. Even moderate physical activity produces breathlessness that can be socially isolating and contributes to deconditioning.

Cardiovascular burden. Chronic low oxygen levels increase pulmonary arterial pressure, over time causing right heart strain (cor pulmonale). Emphysema is a recognized independent risk factor for cardiovascular morbidity.

Mental health. The progressive, irreversible nature of emphysema — combined with activity limitation and social withdrawal — is associated with elevated rates of anxiety and depression.

Sleep quality. Nocturnal oxygen desaturation is common and disrupts restorative sleep, compounding fatigue and cognitive effects.

For individuals with SERPINA1 high-risk variants or confirmed AATD, disease onset can occur significantly earlier than in typical smoking-related emphysema — sometimes in the fourth or fifth decade of life, even in non-smokers or light smokers. This earlier onset is a key reason AATD remains under-detected: clinicians less often suspect emphysema in patients under 45.

Working with your emphysema risk result

A higher genetic risk score means your lungs may be more susceptible to emphysema-causing damage, particularly from cigarette smoke and other pulmonary irritants. It is not a certainty that emphysema will develop — exposure is the primary driver, and genetics is the susceptibility modifier. Here are the actions with the strongest evidence base, ordered by impact:

1. Stop smoking or never start. This is the single most important modifiable factor. Even long-term heavy smokers who quit show a slower rate of lung function decline compared with those who continue. For individuals with CHRNA5 high-risk variants, standard willpower-based cessation may be harder — pharmacological support (varenicline, bupropion, or nicotine replacement therapy) is recommended and effective. Discuss your genetic result with a clinician who can guide cessation pharmacotherapy.

2. Test for alpha-1 antitrypsin deficiency (AATD) if indicated. Anyone with unexplained breathlessness before age 45, emphysema without significant smoking history, or a family history of early-onset lung disease should ask their clinician about SERPINA1 testing (a blood test measuring AAT levels and genotype). Augmentation therapy (weekly intravenous infusions of purified AAT) is an approved treatment for individuals with confirmed AATD and established emphysema, shown to slow lung function decline.

3. Avoid second-hand smoke and occupational exposures. If your work involves coal dust, silica, grain dust, isocyanates, or cadmium fumes, discuss appropriate respiratory protection and exposure monitoring with your occupational health provider. These exposures compound genetic susceptibility.

4. Annual spirometry monitoring. Individuals with SERPINA1 variants, significant smoking history, or unexplained respiratory symptoms benefit from regular spirometry to detect early airflow limitation before significant symptoms appear. Early detection enables earlier intervention.

5. Prevent respiratory infections. Viral and bacterial respiratory infections accelerate emphysema progression by triggering acute exacerbations. Stay current on influenza and pneumococcal vaccination. Discuss COVID-19 vaccination with your clinician, as COVID-19 respiratory illness has been associated with worsening of obstructive lung disease.

6. Engage in pulmonary rehabilitation. For individuals with established emphysema or significant airflow limitation, structured pulmonary rehabilitation programs combining supervised exercise, breathing techniques, and education are the highest-evidence non-pharmacological intervention for improving exercise capacity and quality of life.

Related traits and genes

CHRNA5 at 15q25.1: a hub gene for smoking and lung health. The 15q25.1 locus tagged by CHRNA5 has an extensive trait neighborhood. Smoking cessation genetics (TRAIT017914) and smoking initiation risk (TRAIT018572) both map to overlapping genomic territory, reflecting the dual nature of this locus: it shapes both the behavioral tendency to smoke and the biological response of lung tissue to smoke. If your ExomeDNA report covers smoking-related traits, reviewing those results alongside your Emphysema Risk result provides a more complete picture of your personal risk architecture.

Respiratory adjacency: non-allergic asthma. Non-Allergic Asthma (TRAIT_030553) shares airway inflammation biology with emphysema and COPD. While the mechanisms differ — asthma is largely reversible airflow obstruction from inflammation, emphysema is irreversible structural destruction — the two conditions frequently co-occur (overlap syndrome, sometimes called ACOS), and GWAS signals from both traits illuminate the same pulmonary immune and structural pathways.

Lifetime smoking exposure. Lifetime Smoking Genetics (TRAIT_001003) captures the total integrated smoking burden across a lifespan, which is directly relevant to emphysema risk accumulation. Individuals with both higher emphysema genetic susceptibility and higher lifetime smoking genetic propensity face a compounded exposure-susceptibility burden.

Liver and systemic protein production. SERPINA1 is primarily produced in the liver. Liver Cirrhosis Risk Genetics (TRAIT_052902) shares the liver as a central organ where protein production capacity and dysfunction intersect with systemic disease. Conditions that impair liver function can secondarily reduce AAT output, compounding lung vulnerability in AATD carriers.

Gene-level biology. The four genes driving this trait's associations — SERPINA1, CHRNA5, SERPINA2, and MFSD9 — represent a convergence of antiprotease defense, neuropharmacological addiction biology, and transporter function. SERPINA1 and SERPINA2 are members of the serpin superfamily, one of the largest families of protease inhibitors in biology. Their co-location at 14q32 reflects evolutionary duplication and functional specialization in the lung's protective system.

Frequently asked questions

Does a higher emphysema risk score mean I will develop emphysema? No. The score reflects inherited susceptibility — how your lungs respond to damaging exposures. Emphysema is primarily driven by cigarette smoke and other pulmonary irritants. Without significant exposure, even high-risk individuals are unlikely to develop clinically significant disease. The score tells you how much your lungs' defenses matter relative to those exposures, not whether disease is predetermined.

What is alpha-1 antitrypsin deficiency (AATD), and should I be tested? AATD is an inherited condition in which SERPINA1 variants cause reduced or dysfunctional alpha-1 antitrypsin protein, removing a key protector of lung tissue from elastase damage. It is significantly under-detected and often labeled as COPD without AATD testing. If your ExomeDNA report highlights SERPINA1 variants, or for individuals with unexplained breathlessness before age 45, emphysema without heavy smoking, or relevant family history, discuss AAT testing (blood level + genotype) with your clinician. An approved augmentation therapy exists for confirmed AATD with established lung disease.

Why does CHRNA5 affect both smoking addiction and lung tissue? The 15q25.1 chromosomal region where CHRNA5 sits influences nicotinic acetylcholine receptor function in the brain's reward circuits and simultaneously has pleiotropic effects on lung tissue biology. The rs16969968 variant in CHRNA5 makes nicotine signaling more reinforcing — increasing nicotine dependence — while the same locus independently increases lung tissue vulnerability to smoke-induced damage. This dual mechanism explains in part why some individuals find cessation harder and also develop emphysema more rapidly than population averages would predict.

Can I slow emphysema progression if it has already started? Yes, significantly. Smoking cessation at any stage slows the rate of lung function decline measurably — the earlier, the better, but even cessation after years of disease produces benefit. Pulmonary rehabilitation improves exercise tolerance and quality of life with established emphysema. For AATD, augmentation therapy slows progression. Avoiding additional exposures (secondhand smoke, occupational dust/fumes) reduces the rate of further alveolar destruction.

What is the VA Million Veteran Program and why does it matter for this result? The VA Million Veteran Program is a large biobank study that has enrolled hundreds of thousands of US veterans with linked electronic health records, genomic data, and clinical phenotype information. Its scale and multi-ancestry composition make it one of the most statistically powerful datasets for identifying GWAS associations. The emphysema findings in Verma et al. (2024) were identified in this uniquely large and diverse cohort, which improves confidence that the signals generalize beyond predominantly European-ancestry populations used in earlier GWAS.

How is emphysema different from asthma? Asthma involves reversible airway inflammation that responds to bronchodilators and anti-inflammatory treatment. Emphysema involves permanent structural destruction of alveolar walls that does not reverse. On spirometry, asthma typically shows variable airflow obstruction with significant reversibility after bronchodilator; emphysema shows fixed airflow obstruction with minimal reversibility. The two conditions can co-exist (ACOS), and both are linked to airway inflammation genetics, but their mechanisms, progression patterns, and treatments differ substantially.

References

1. Verma A et al. (2024). Diversity and scale: Genetic architecture of 2,068 traits in the VA Million Veteran Program. Science, PMID 39024449.

ExomeDNA genetic results are for wellness and educational purposes only. Consult a clinician for personalized health guidance.