How well a pair of lungs works is heritable and measurable, and it is also mostly the result of what has been breathed. Both halves are true, and the second one is larger.
Lung function is measured by asking someone to blow into a tube. Two numbers come out: how much air leaves in the first second (FEV1), and what share of the total that is (FEV1/FVC). The ratio is the one that says whether airflow is obstructed, which is how COPD is defined.
These are among the better predictors of illness and death in medicine, and they run in families.
A meta-analysis of 20,890 people across four large cohorts identified eight loci associated with FEV1/FVC. That is a real and reproducible result: the shape of a person's lungs and airways is partly inherited.
It is also small. Everything found together explains a modest share of the variation between people, and the variation between a smoker and a non-smoker dwarfs it.
Lung function is the clearest case on this site of a trait that is genuinely heritable and almost entirely about environment.
Both statements are true at once. Within a group of people who have breathed similar air, some of the difference is inherited. Between a person who smoked for thirty years and one who did not, almost none of it is.
A genotype here cannot tell anyone their lung function, and it certainly cannot tell them that smoking is safer for them. If anything the finding runs the other way: people with lower baseline function have less to lose before it matters.
Spirometry is cheap, quick and direct. If breathlessness, a persistent cough or an occupational exposure is the reason for the question, that test answers it — and it answers it about the lungs actually in the room rather than about a population average.
The source. Hancock et al. (Nat Genet 2010) meta-analysed genome-wide association studies of FEV1 and FEV1/FVC in 20,890 participants of European ancestry from four CHARGE Consortium cohorts — the Atherosclerosis Risk in Communities study, the Cardiovascular Health Study, the Framingham Heart Study and the Rotterdam Study — identifying eight loci associated with FEV1/FVC.
The variants recorded here. rs2070600 in AGER, encoding the receptor for advanced glycation end-products (RAGE), which is constitutively expressed at high levels in lung tissue and participates in inflammatory signalling and alveolar repair; and rs11727189 in the GSTCD region of chromosome 4q24, a locus repeatedly implicated in lung function whose causal gene and mechanism remain unresolved.
Effect size and context. The variance in FEV1/FVC explained by all identified common variants is small in absolute terms and is dwarfed by the effect of smoking, occupational exposure and childhood respiratory illness. Spirometric measures are strong predictors of morbidity and mortality; the genetic contribution to them is real, reproducible and clinically inconsequential at the level of an individual.
Clinical boundary. Airflow obstruction is defined and diagnosed spirometrically, with post-bronchodilator FEV1/FVC below a defined threshold. No genotype is used in diagnosis, staging or management of COPD or asthma, and no position here modifies advice about smoking or occupational exposure.
What a 23andMe/AncestryDNA export or raw VCF can and can't tell you about Pulmonary Function (Lung Capacity) comes down to these specific, well-studied positions — not a diagnosis.
No, and the test that does takes about a minute. Spirometry measures the lungs in the room; these positions shift a population average by a little.
No. Within a group who have breathed similar air, some of the difference is inherited. Between a thirty-year smoker and a non-smoker, almost none of it is. If anything, lower baseline function means less margin before it matters.
FEV1 is how much air leaves the lungs in the first second; FVC is the total. The ratio says whether air is being obstructed on the way out, which is what defines COPD — a small total with a normal ratio is a different problem from a normal total that empties slowly.
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