Is Asthma Genetic? What 52 DNA Regions and a 2025 Biologic Approval Mean for Your Family

Is Asthma Genetic? What 52 DNA Regions and a 2025 Biologic Approval Mean for Your Family

This article is for educational purposes only. It is not a substitute for advice from a licensed physician, board-certified medical geneticist, or board-certified genetic counselor. For any decisions about testing, treatment, or care, consult a qualified clinician. In emergencies, call 911.

Bottom line: A 2025 gene-mapping study found 52 DNA regions linked to asthma risk, 31 of them newly identified in East Asian populations. None of them work alone. Asthma comes from many small genetic nudges added together with things like allergens and childhood colds. It is not one “asthma gene” passed down the way some rare conditions are. A direct-to-consumer (DTC) polygenic score — a home DNA test you order yourself, without a doctor, like the one 23andMe reports — reflects that same spread-out pattern. It is a broad group estimate, not a forecast for one person. Meanwhile, a newly approved biologic drug shows something important: the “eosinophilic” genetic subtype this research describes is no longer just a label in a paper. It is now a treatable group with its own FDA-approved drug.

What you’ll learn:

• Why asthma is called “polygenic,” and how that differs from single-gene conditions
• How to turn a gene finding or a DTC risk score into a real number — and how a lab diagnosis differs from a consumer genetic report
• What the newest FDA-approved biologic drug means if your family’s asthma leans toward the eosinophilic type
• How genetic risk information touches insurance, jobs, and family conversations

Why Asthma Runs in Families: The Polygenic, Not Single-Gene, Explanation

Asthma is a long-term lung disease. It causes swelling and narrowing in the airways, which leads to wheeze, cough, a tight chest, and shortness of breath. Doctors have known for decades that it runs in families. What’s new is the ability to say why, down to specific spots in human DNA.

A 2025 study in the journal Nature Communications looked at genetic data from a large international project called the Global Biobank Meta-analysis Initiative. That project combined asthma data from more than 20 biobanks across many countries and ancestries. Researchers started with 18,549 people who had asthma and 322,655 people who did not. They then added a further 1,100 cases and 2,506 controls from East Asian groups. The result: 52 spots in the genome — called loci — that are statistically linked to asthma risk. Of those, 31 are newly identified in East Asian populations.

Here is the key point: no single locus (gene location) causes asthma by itself. Each one nudges risk up or down by a small amount. MedlinePlus Genetics, a public resource from the National Institutes of Health, describes asthma as a complex disorder. Many gene variants act together with things in the environment. It is not a single-gene pattern. That is quite unlike a lung condition such as alpha-1 antitrypsin deficiency. There, one altered gene, passed down in a predictable way, is enough on its own to cause disease. Asthma does not work like that.

Most of the biology centers on “type-2” immune signaling. This is a group of chemical messengers — including interleukin-4, interleukin-5, interleukin-13, and a molecule called TSLP — that drives swelling in the airway lining. Genes in this pathway make the airway lining overly sensitive, a state doctors call airway hyperresponsiveness. This pattern shows up most strongly in the eosinophilic phenotype. That is the specific form the disease takes when a type of white blood cell, the eosinophil, builds up in the airways.

Several named gene regions from the 2025 study are worth knowing, since you may see them in a DTC report or a research summary:

• CD36: a variant here was linked to lower asthma risk. Lab tests showed it changes how active this gene is in immune cells involved in the type-2 response.
• SMAD2 (on chromosome 18): tied to airway remodeling — the long-term structural changes seen in some asthma cases.
• TSLP, PPP1R11, and GSDMB: three regions specifically linked to the eosinophilic subtype.

Think of it like rain feeding a river. No single raindrop causes a flood. It is the sum of many small contributions, combined with the terrain — your own environment and exposures — that decides the outcome.

Section recap: Asthma risk comes from dozens of DNA regions working together with things around you, not one inherited gene. A primary care doctor or allergist can help turn a family history of asthma into a personal conversation about your own risk.

How Much Does Genetics Raise Your Risk? Turning Gene Data Into Real Numbers

A “genome-wide significant locus” is a statistical finding. It means the gap between people with and without asthma at that DNA spot is unlikely to be due to chance. It does not, by itself, tell you how much that spot changes any one person’s odds. That difference matters when a DTC report shows you a list of genetic markers.

Take the CD36 variant, rs75326924, as a real example. Researchers found it was more common in people without asthma than in people with asthma. Lab work confirmed it changes gene activity in immune cells that drive type-2 inflammation. That is a real, repeated, protective link. It is also a small one. Carrying it does not mean asthma is off the table, and not carrying it does not mean asthma is likely. Each of the 52 loci shifts overall risk by a modest amount. The effects add up across dozens of regions rather than piling up in one.

This is exactly what a DTC polygenic score is built to do. It adds up many small genetic effects into one number, one that estimates how your odds compare with a reference group. According to 23andMe’s own published report materials, its asthma score is built from tens of thousands of contributing gene variants. It is calculated separately for several ancestry groups, including European, East and Southeast Asian, Hispanic/Latino, South Asian, Sub-Saharan African/African American, and Northern African/Western Asian ancestries. That is a group-level estimate. It is not a diagnosis, and it is not a fixed lifetime number for one person.

To put this in real terms: asthma affects millions of children and adults in the US. The CDC’s national surveillance data show it stays common across all age groups, with rates that vary by state, race, and ethnicity. A relative-risk figure only means something next to that real background rate. Here is a simple, round-number example: suppose the baseline rate were 8 out of 100 people. A 20% relative increase would move that to roughly 9 or 10 out of 100 — a modest shift, not a near-certainty. Read any specific number in a DTC report the same way: as a small move from a baseline, not a verdict.

A useful comparison: a genetic risk score is like a weather forecast that says “30% chance of rain” for your town. It does not guarantee rain on your specific yard. It shifts the odds. It does not decide the outcome.

Section recap: Relative-risk numbers from gene studies or DTC reports only make sense next to the real population rate. Research shows that asthma risk shifts are usually modest, not decisive. A pulmonologist or allergist can help put any specific number into context for your own health history.

Genetic Test vs. Clinical Diagnosis: What a Direct-to-Consumer (DTC) Report Can and Cannot Tell You

There is no insurance-covered genetic test that diagnoses asthma the way, for example, BRCA testing flags inherited cancer risk. Asthma is diagnosed in the clinic, not through DNA. A doctor typically uses three tools:

• Spirometry: a breathing test that measures how much and how fast air moves in and out of your lungs.
• Bronchodilator response test: checks whether airflow improves after you use an inhaled medicine.
• A detailed symptom and family history, taken directly by the doctor.

A DTC polygenic report, like 23andMe’s Asthma report, measures something else: a weighted statistical estimate built from population gene data, not a measurement of your own lungs. It cannot tell you whether you currently have asthma, and it cannot replace spirometry if you have symptoms.

It also cannot tell you which type of asthma you might be prone to. Whether someone has the eosinophilic subtype is not something genetic testing determines in clinical practice today. That comes from a blood eosinophil count and a fractional exhaled nitric oxide (FeNO) test — a breath test that measures airway inflammation. Both are used in current US asthma guidelines to guide treatment choices. Guidance from the American Academy of Allergy, Asthma & Immunology likewise says that biologic-drug eligibility depends on phenotype and biomarker testing, not DNA results.

It helps to know that DTC testing is not one single category. Some consumer companies sell wellness-style reports, like polygenic scores, straight to individuals with no doctor’s order involved. Other testing companies work through a clinical channel instead. A doctor or genetic counselor orders the test. Those results are usually more targeted and more medically useful — most often for single-gene conditions, not a spread-out trait like asthma. Neither kind of testing replaces spirometry or a clinical eosinophil-and-FeNO check when asthma symptoms show up.

An everyday comparison: a DTC polygenic report is like a weather station reporting average rainfall trends for your zip code. Spirometry and FeNO testing are like checking the rain gauge in your own backyard right now. Both are useful, but only one tells you what is happening in your lungs today.

Section recap: A DTC polygenic score is a population-based estimate, while a real asthma diagnosis relies on spirometry, a bronchodilator test, and a doctor’s exam. Anyone with active symptoms — wheeze, a cough that won’t quit, or breathlessness with exertion — should see a doctor rather than lean on a genetic report.

Reading Your Results: Risk Score, Diagnosis, and Phenotype Are Not the Same Thing

If a DTC report flags a high asthma polygenic score, the most useful next step is understanding exactly what that number says — and does not say. It is an estimate of how likely asthma is across a population, built by combining thousands of small genetic effects.

It is not a diagnosis. It also does not work like a single-gene test. There, a lab might flag a “variant of uncertain significance.” That is a result not yet clearly linked to disease, and it means waiting for more research. A polygenic score does not carry that kind of individual warning flag. Its main limitation is different. Most of the research behind it, including much of the 2025 loci discovery, comes from specific studied groups of people. How well those findings carry over to every ancestry a DTC company claims to cover is still being studied.

A positive score also says nothing about which form the disease might take. It cannot say whether a future or existing case would lean eosinophilic, driven by type-2 inflammation, the kind biologic drugs target. Or it could lean non-eosinophilic, allergic, or non-allergic instead. Two people with similar polygenic scores could end up with very different symptoms, severity, and treatment needs. National guidance on step-by-step asthma treatment also relies on symptoms and biomarkers, not a genetic score, when deciding whether to escalate medication.

The practical takeaway: treat active symptoms — not a DTC score — as the trigger for a clinic visit. Wheeze, a cough that will not quit, or breathlessness during exercise are what should send you to a doctor or pulmonologist. A genetic result belongs in that conversation as background, mentioned alongside your symptoms — not as a stand-alone reason to seek treatment on its own.

Think of it like a smoke detector versus a home inspection report. The report might note that a home sits in a neighborhood with slightly higher fire risk. Only an actual smoke alarm going off means it is time to act right now.

Section recap: A DTC asthma score is background, not a phenotype label or a diagnosis. It cannot say whether a future case would be eosinophilic or how severe it might be. Bring both your genetic result and any symptoms to a primary care doctor or allergist for an accurate clinical picture.

Can Asthma Be Prevented or Caught Early in an At-Risk Family?

Genetic risk for asthma is not destiny. Prevention research focuses on cutting exposure to known environmental triggers, not on changing your genes. The CDC names several triggers you can act on, no matter your genetic background:

• Secondhand smoke
• Dust mites
• Pet dander
• Air pollution
• Respiratory infections in childhood

For a family with a genetic or family-history-based higher risk, cutting these exposures is a reasonable, evidence-based step. That means especially tobacco smoke, and allergen buildup at home where possible.

Getting prompt care for childhood respiratory infections, and following up early on repeat wheeze episodes, also matters. Genes linked to asthma risk overlap with genes linked to other type-2 allergic conditions, such as eczema and hay fever. Catching early symptom patterns, not genetic screening, is what current pediatric care emphasizes.

It is worth being clear about what is not currently recommended: population-wide genetic screening for asthma risk is not part of US preventive-care guidelines. In 2017, the US Preventive Services Task Force looked at the broader question of asthma screening. It found there was not enough evidence to say whether screening healthy, symptom-free children and teens for asthma helps or hurts. That finding applies only to children with no signs of asthma. It does not apply to a child who already has wheeze or a lasting cough. That child should be seen by a clinician, regardless of any DTC result.

An analogy that helps here: cutting household triggers is like weatherproofing a house that sits in a flood-prone area. It will not change the underlying flood risk of the land, but it meaningfully lowers the odds of real water damage.

Section recap: Cutting known triggers and getting prompt care for childhood wheeze are evidence-based steps, not guarantees. There is no recommended genetic screening program for asthma. A pediatrician or family doctor is the right resource for checking a child’s actual symptoms.

The Newest Asthma Biologic: What Depemokimab (Exdensur) Means for Eosinophilic Asthma

The genetics described above connect directly to a real treatment choice for one group of patients: those with severe, eosinophilic-type asthma. On December 16, 2025, the US Food and Drug Administration approved depemokimab-ulaa, brand name Exdensur, made by GSK. It is a long-acting antibody drug given as an add-on treatment just twice a year, roughly every 26 weeks. It is approved for patients age 12 and older with severe asthma and an eosinophilic phenotype.

Depemokimab is a lab-made protein that blocks interleukin-5 (IL-5). IL-5 is one of the same type-2 signaling molecules involved in the pathway those genetic loci point to. In the Phase 3 SWIFT-1 trial, it cut annualized exacerbation rates by 58% compared with placebo over 52 weeks. Exacerbations here mean asthma flare-ups bad enough to need extra treatment. In the companion SWIFT-2 trial, the cut was 48%.

Depemokimab is the newest member of a small family of biologic drugs that all target the same IL-5 signal:

• Mepolizumab
• Reslizumab
• Benralizumab
• Depemokimab (Exdensur) — the newest, given only twice a year

The evidence behind this drug class is strong. An earlier pivotal trial, MENSA, showed that mepolizumab significantly cut exacerbations in patients chosen by their high blood eosinophil count. That result helped establish the eosinophil count as the key test for who should get anti-IL-5 therapy. A Cochrane review of the whole drug class confirmed that the benefit is concentrated in patients with a high eosinophil count. That is why doctors pick patients by blood test, not by genes.

This matters for a reader with a family history and a DTC score in hand. Whether someone qualifies for depemokimab or similar biologics is decided by blood eosinophil count, FeNO testing, and a specialist visit — not by a genetic report. Global treatment guidance places biologic therapy at the higher steps of a step-by-step framework. It is used only for asthma that is severe and not well controlled by other drugs. If your genetics point toward the eosinophilic type, and your symptoms are more than occasional, that is worth mentioning. Ask a pulmonologist or allergist about biomarker testing. It is not a reason to start biologic therapy on your own.

One caveat worth flagging: Health Canada’s approval status and timeline for depemokimab were not independently confirmed as of this article’s research date. Canadian readers should check current status directly with a provider or pharmacy.

Picture a biologic drug like a targeted fire suppressant, built for one specific kind of fire. It works — and is approved — only for the fire it was designed to fight. Here, that means eosinophilic inflammation confirmed by a blood test, not a genetic score alone.

Section recap: Depemokimab (Exdensur) is a twice-yearly, FDA-approved biologic for severe eosinophilic asthma, backed by strong trial data. Whether you qualify depends on eosinophil and FeNO testing, not genetics. An allergist or pulmonologist can check whether a biologic-eligibility workup makes sense for ongoing symptoms.

What This Means for Your Kids and Siblings: Family Risk Without Cascade Testing

In some genetic conditions, one relative’s positive test triggers “cascade testing” — systematically testing close relatives for that same, single known mutation. Asthma does not work this way, because there is no single family variant to test for. Risk is spread across dozens of loci, each with a small effect.

What does carry over in a family is risk-awareness, not a testable gene. MedlinePlus Genetics notes that having a parent or sibling with asthma raises a child’s risk but does not guarantee the child will develop it. Parents with asthma, or with a high DTC polygenic score, may reasonably choose to watch their children more closely. Early wheeze, a lasting cough, or breathlessness with exercise are worth mentioning at pediatric visits, along with the family history itself.

It also helps to know that asthma-risk genes overlap heavily with genes linked to other type-2 allergic conditions, like eczema and hay fever. A family with a strong asthma history may see any mix of these conditions across generations, not just asthma alone. That overlap is a research finding about shared biology, not a prediction that any one relative will develop all three.

The clearest way to frame this for a family conversation: most children of a parent with asthma will not develop asthma themselves. Genetics raises the odds by a measurable but modest amount. It does not decide the outcome.

In practice, a pediatric visit is the right place to raise a family asthma history. Notes about eczema, hay fever, or food allergy elsewhere in the family belong there too. A pediatrician can use that context to decide how closely to watch a child’s breathing during colds, exercise, or pollen season. The family history alone does not call for a workup on its own.

An analogy: family asthma risk is more like a shared weather pattern across a household than a single object passed hand to hand. Everyone in the house lives under a similar climate, but each person’s actual day still depends on their own exposures.

Section recap: Asthma risk is spread across many genes, so there is no single variant to test relatives for. The practical response is closer attention, not genetic testing of family members. A pediatrician or family doctor can advise on watching children with a strong family history.

Insurance, Employment, and Disclosure: What GINA and the ACA Actually Cover

A common worry after seeing a high DTC result is whether it could affect insurance or a job. In the United States, the Genetic Information Nondiscrimination Act (GINA), passed in 2008, bars health insurers and employers from making decisions based on genetic information. That includes results from a DTC polygenic report and even your family medical history. Here is what GINA covers, and where its protection stops:

Protection	What it covers	What it does NOT cover
GINA Title I (2008)	Health insurance: insurers cannot use a genetic test result or family history to deny coverage or charge more	Life insurance, disability insurance, and long-term-care insurance — these can still legally use genetic information in most states
GINA Title II (2008)	Employment: hiring, firing, and promotion decisions cannot be based on genetic information, including family history	Some very small employers may fall outside GINA’s employment rules
Affordable Care Act (ACA)	For a confirmed asthma diagnosis: ACA-compliant health plans cannot deny coverage or charge more because of it	Plans that are not ACA-compliant, such as some short-term limited-duration plans

Two points are worth underlining. First, GINA does not reach life, disability, or long-term-care insurance. Those policies can still legally weigh your genes in most states. Second, under GINA, “genetic information” includes your family’s medical history, not just lab results. That already covers the kind of family-history worry many readers bring to this topic.

The ACA point above is different from GINA. It applies once someone already has a confirmed asthma diagnosis, not just a genetic risk flag. That is a separate legal protection for a separate situation — a diagnosis, not a risk estimate.

Readers in Canada face a different landscape. In Canada, access to severe-asthma biologics generally depends on decisions made by each province’s public drug plan. Those decisions can lag behind or differ from US FDA approval dates. Coverage status for depemokimab specifically was not confirmed as of this article’s research date. A Canadian reader interested in a newly FDA-approved biologic should check directly with a provincial drug plan or a specialist rather than assume it is immediately available.

On family disclosure: there is no legal requirement to share a DTC result with siblings or children, and the choice is personal. The genetic overlap and shared exposures within a family are already well documented. Because of that, many people choose to mention a family asthma history at check-ups regardless of a specific DTC score, simply because it is useful clinical context.

Think of GINA as a fence around one specific yard. It clearly protects health insurance and employment decisions, but that fence does not reach the neighboring yards of life, disability, or long-term-care insurance.

Section recap: GINA protects US health insurance and employment decisions based on genetic information, including family history, but not life, disability, or long-term-care insurance. Canadian biologic access generally depends on provincial drug plans, and coverage for depemokimab was not confirmed as of this article’s research date. A genetic counselor is a clinician trained to help you understand what a gene test result does and does not mean. Search a directory at NSGC.org for disclosure and coverage questions specific to your situation.

Frequently Asked Questions

Does a positive polygenic score mean I will develop asthma?
No. A DTC polygenic score is a population-level estimate built from many small genetic effects, not a forecast for one person. Most people with a high score never develop symptomatic asthma, and the score cannot replace a clinical evaluation if symptoms appear.

Will my kids or grandkids inherit my asthma risk?
They inherit a modestly higher statistical risk, not a guaranteed outcome. Having a parent with asthma raises a child’s odds, but most children of an affected parent do not develop asthma themselves. There is also a documented overlap with related allergic conditions like eczema and hay fever, so a family history can show up in different, related ways.

Will this affect my health or life insurance?
US health insurance and employment decisions cannot legally be based on genetic information, including a DTC result or family history, under GINA. GINA does not cover life, disability, or long-term-care insurance, which can still factor in your genes in most states.

Can my employer find out and use this against me?
GINA’s Title II specifically bars US employers from using genetic information, including DTC results, in hiring, firing, or promotion decisions. It does not cover every possible workplace scenario, so specific concerns are worth raising with an employment attorney or HR compliance resource if they come up.

Should I get a second opinion or see a specialist?
If you have active symptoms — wheeze, a lasting cough, or breathlessness with exertion — yes. A pulmonologist or allergist can run spirometry and, where relevant, eosinophil and FeNO testing to determine your phenotype and treatment options. A DTC score alone is not a reason for urgent care. Ongoing symptoms always are.

Summary

Asthma is a polygenic condition. Dozens of small-effect DNA regions, not one dominant gene, combine with things in your environment to shape overall risk. A 2025 gene-mapping study expanded the known map to 52 regions. Several of those are tied to the eosinophilic subtype. A DTC polygenic score reflects that same spread-out pattern: useful as background, not as a diagnosis or a phenotype label.

Clinically, nothing about this changes how asthma gets diagnosed. Spirometry, a bronchodilator test, and a doctor’s exam still come first. What has changed is treatment. The eosinophilic subtype this research describes now has its own twice-yearly biologic option. That option is depemokimab (Exdensur), FDA-approved in December 2025 on the strength of large drops in flare-ups. Family risk is real but modest, and cascade testing does not apply here. US legal protections under GINA cover gene-based information in health insurance and employment, with clear limits elsewhere. None of this replaces a conversation with your doctor or a genetic counselor about your own family’s situation.

This article is for educational purposes only. It is not a substitute for advice from a licensed physician, board-certified medical geneticist, or board-certified genetic counselor. For any decisions about testing, treatment, or care, consult a qualified clinician. In emergencies, call 911.

References

1. Multi-trait genetic analysis of asthma and eosinophils uncovers pleiotropic loci in East Asians (2025), Nature Communications — https://www.nature.com/articles/s41467-025-60405-0
2. GSK press release announcing US FDA approval of depemokimab-ulaa (Exdensur) for severe eosinophilic asthma, 2025-12-16 — https://www.gsk.com/en-gb/media/press-releases/
3. Zhou et al. (2022), Global Biobank Meta-analysis Initiative: Powering genetic discovery across human diseases, Cell Genomics — https://www.cell.com/cell-genomics/
4. Asthma, National Heart, Lung, and Blood Institute (NHLBI/NIH) — https://www.nhlbi.nih.gov/health/asthma
5. Asthma, MedlinePlus Genetics (NIH/National Library of Medicine) — https://medlineplus.gov/genetics/condition/asthma/
6. Most Recent National Asthma Data, Centers for Disease Control and Prevention (CDC) — https://www.cdc.gov/asthma/most_recent_national_asthma_data.htm
7. Genetic Discrimination and the Genetic Information Nondiscrimination Act (GINA), National Human Genome Research Institute (NHGRI, NIH) — https://www.genome.gov/about-genomics/policy-issues/Genetic-Discrimination
8. 2020 Focused Updates to the Asthma Management Guidelines, National Asthma Education and Prevention Program (NAEPP), NHLBI/NIH — https://www.nhlbi.nih.gov/resources/2020-focused-updates-asthma-management-guidelines
9. Screening for Asthma in Children and Adolescents, US Preventive Services Task Force (USPSTF), 2017 — https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/asthma-in-children-and-adolescents-screening
10. Global Strategy for Asthma Management and Prevention, Global Initiative for Asthma — https://ginasthma.org/gina-reports/
11. Farne, Wilson, Powell, Bax & Milan, Anti-IL5 therapies for asthma, Cochrane Systematic Review — https://www.cochranelibrary.com/cdsr/reviews
12. Ortega et al. (2014), Mepolizumab treatment in patients with severe eosinophilic asthma (MENSA trial), New England Journal of Medicine — https://www.nejm.org/doi/full/10.1056/NEJMoa1403290
13. AAAAI practice guidance on severe eosinophilic asthma and biologic-therapy eligibility, American Academy of Allergy, Asthma & Immunology — https://www.aaaai.org/

Last updated: 2026-09-21

Author: genelumen editorial team. This article aggregates 13 sources from peer-reviewed medical literature and public health agencies (tier 1=9 / tier 2=4). Sources include NIH (NHLBI, NHGRI, MedlinePlus Genetics), the CDC, the FDA, the USPSTF, the Global Initiative for Asthma, the AAAAI, and Cochrane. Journals cited include Nature Communications, Cell Genomics, and the New England Journal of Medicine.

This article is for educational purposes only and is not a substitute for medical advice from a licensed physician, board-certified medical geneticist, or board-certified genetic counselor. In emergencies, call 911 (US/Canada) or 119 (Japan).

Related: Genetic Diseases category

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