The only reliable way to know if you carry the CCR5-delta32 mutation is through a genetic test, either ordered by a physician or purchased through a direct-to-consumer DNA service. There is no symptom, blood marker, or family history pattern that can confirm or rule out the mutation on its own. The test itself is straightforward, typically involving a blood draw or cheek swab, and the result places you into one of three categories: no copies, one copy, or two copies of the deletion. What makes the answer worth digging into is that each of those categories carries a meaningfully different set of health implications, from near-complete resistance to HIV infection to an elevated risk of severe West Nile virus disease.
What the Delta 32 Mutation Actually Is
CCR5 is a protein that sits on the surface of certain immune cells. It acts as a docking point, helping immune-signaling molecules called chemokines guide white blood cells to sites of infection. Unfortunately, HIV-1 also uses CCR5 as a doorway to enter and infect those cells. The delta 32 mutation is a 32-base-pair chunk of DNA missing from the gene that codes for CCR5. When a person inherits two copies of this deletion, their cells produce little to no functional CCR5 protein on the surface, which leaves HIV-1 with no way in.1PubMed Central. Legacy of a magic gene-CCR5-∆32: From discovery to clinical benefit in a generation
Inheriting one copy (being a “heterozygous carrier”) still produces some CCR5, so the protection is partial. Inheriting zero copies means the gene is working normally. This distinction between one copy and two is not a minor footnote; it is the central fact that shapes everything from HIV risk to cardiovascular health to West Nile vulnerability.
How to Get Tested
There are two main routes to finding out your CCR5-delta32 status. The first is a clinical genetic test, ordered through a doctor or genetic counselor. These tests use polymerase chain reaction (PCR) to amplify the CCR5 gene region and detect whether the 32-base-pair deletion is present. Some labs use restriction enzyme digestion after PCR to distinguish between genotypes; others rely on size-separation techniques that can tell whether you have one shortened copy of the gene or two.2PubMed Central. Chemokine receptor CCR5 Delta 32 genetic analysis using multiple specimen types and the NucliSens Basic Kit Clinical-grade assays have been validated using multiple sample types, including standard blood draws, dried blood spots, and buccal (cheek) swabs, and they produce highly concordant results across methods.
The second route is direct-to-consumer (DTC) genetic testing. Several well-known consumer genomics companies genotype the CCR5 region as part of their broader chip-based analysis. If you have already submitted a saliva sample to one of these services, your raw data file may contain the relevant variant, often labeled as rs333. You can download that raw data and look it up, or use third-party analysis tools that flag it. The trade-off is that consumer genotyping chips are designed for breadth rather than depth. They read hundreds of thousands of genetic positions across your genome, but they do not sequence the CCR5 gene in full. For most people asking a straightforward yes-or-no question about delta 32 status, this level of resolution is sufficient. But if you need a result for clinical decision-making, a dedicated lab test is the more reliable choice.
A third, newer option involves next-generation sequencing (NGS), which reads the CCR5 gene base by base. NGS can catch not only the delta 32 deletion but also rarer variants in the same gene region that might affect CCR5 function in other ways.3PubMed Central. Genotyping of the CCR5 chemokine receptor by isothermal NASBA amplification and differential probe hybridization This technology is still more expensive and less widely available for individual testing, but it is the direction the field is heading.
What Your Results Mean
Your test will return one of three possible genotypes. Each carries distinct implications:
- Wild-type (wt/wt): You have two normal copies of CCR5. Your CCR5 protein is produced normally. No delta 32-related protection or risk applies.
- Heterozygous (wt/Δ32): You have one normal copy and one deleted copy. You still produce CCR5 protein, but at reduced levels. This may offer partial protection against HIV-1 infection. In a study of women, heterozygous carriers were about 37% less likely to be HIV-1 positive compared to women with two normal copies.4PubMed Central. CC chemokine receptor 5 genotype and susceptibility to transmission of human immunodeficiency virus type 1 in women
- Homozygous (Δ32/Δ32): You have two deleted copies. Your cells produce essentially no functional CCR5. This confers near-complete resistance to HIV-1 infection, regardless of exposure level.1PubMed Central. Legacy of a magic gene-CCR5-∆32: From discovery to clinical benefit in a generation But it also opens the door to certain other risks.
A meta-analysis pooling data across multiple studies confirmed this pattern, finding that homozygous carriers had markedly reduced susceptibility to HIV-1 while heterozygous carriers showed a more complex picture depending on the comparison group used.5PubMed Central. The CCR5-Delta32 Genetic Polymorphism and HIV-1 Infection Susceptibility: a Meta-analysis The takeaway is that one copy and two copies are not just “more or less” of the same thing. They represent qualitatively different biological states.
Who Is Most Likely to Carry It
If your ancestry is Northern or Western European, your chances of carrying at least one copy are meaningfully higher than if your roots lie elsewhere. The delta 32 allele reaches frequencies of roughly 10 to 16 percent in European populations, with the highest concentrations in Scandinavia and the Baltic region and lower frequencies along a gradient toward the Mediterranean.6PubMed. Tracing the evolutionary history of the CCR5delta32 deletion via ancient and modern genomes That north-to-south gradient has been documented across the continent.7PubMed. Is the European spatial distribution of the HIV-1-resistant CCR5-Delta32 allele formed by a breakdown of the pathocenosis due to the historical Roman expansion?
The mutation is rare or essentially absent in populations of East Asian, sub-Saharan African, and Indigenous American descent. Its presence in Latin America appears to be the result of post-Columbian European migration and genetic mixing rather than an independent origin.6PubMed. Tracing the evolutionary history of the CCR5delta32 deletion via ancient and modern genomes So ancestry is not a substitute for testing, but it can give you a rough sense of whether the mutation is likely to be in your family tree at all. If your heritage is entirely East Asian, the odds are very low. If your grandparents came from Sweden, the odds are considerably higher.
Why the Mutation Spread Through Europe
The delta 32 deletion appears to have originated at least 6,700 years ago in the Western Eurasian Steppe region, and strong positive selection drove its frequency upward between roughly 8,000 and 2,000 years ago.6PubMed. Tracing the evolutionary history of the CCR5delta32 deletion via ancient and modern genomes Something was giving carriers a survival advantage over thousands of years, long before HIV existed.
The popular explanation used to be the Black Death, the idea being that plague resistance favored delta 32 carriers and pushed the allele’s frequency up during the 14th century. That story has largely fallen apart. Historians have pointed out that the Black Death’s mortality patterns across Europe actually run in the opposite direction from delta 32 frequency: the heaviest death tolls were in the Mediterranean, which today has the lowest delta 32 rates.8PubMed. The Black Death and AIDS: CCR5-Delta32 in genetics and history A more compelling candidate, based on population-genetic modeling that accounts for the timing and age profile of epidemics, is smallpox. Smallpox killed across all ages, struck repeatedly over centuries, and was a persistent scourge in exactly the right time frame to account for the allele’s selective rise.9PubMed Central. Evaluating plague and smallpox as historical selective pressures for the CCR5-Delta 32 HIV-resistance allele
The West Nile Tradeoff
Carrying two copies of delta 32 is not a uniformly protective genetic jackpot. The same absence of CCR5 that blocks HIV also appears to leave the immune system less able to handle West Nile virus. In cohort studies from Arizona and Colorado, homozygous delta 32 carriers were significantly overrepresented among people who developed symptomatic West Nile virus infection, with odds ratios of roughly 4.4 and 9.1 compared to the general Caucasian population.10PubMed Central. CCR5 deficiency increases risk of symptomatic West Nile virus infection A separate study confirmed that while homozygous carriers were not more likely to become infected with West Nile virus in the first place, they were significantly more likely to develop clinical symptoms once infected.11PubMed Central. CCR5 deficiency is a risk factor for early clinical manifestations of West Nile virus infection but not for viral transmission
Homozygous carriers may also face an increased risk of severe brain inflammation from West Nile, including encephalitis.1PubMed Central. Legacy of a magic gene-CCR5-∆32: From discovery to clinical benefit in a generation If you live in or travel to areas where West Nile is endemic, this is the kind of information that could actually affect your behavior, from mosquito-prevention measures to conversations with your doctor about unusual fevers after a bite.
Effects on Inflammation and Heart Health
CCR5 is not just about infectious disease. The receptor plays a role in inflammation broadly, and carrying the delta 32 deletion appears to dial down certain inflammatory processes. In a study of more than 800 people, carriers had lower levels of C-reactive protein (a standard marker of systemic inflammation), thinner carotid artery walls (an indicator of less atherosclerotic buildup), and substantially fewer cardiovascular events over a decade of follow-up.12PubMed. Common CCR5-del32 frameshift mutation associated with serum levels of inflammatory markers and cardiovascular disease risk in the Bruneck population Carriers also showed higher HDL cholesterol and lower triglycerides, both favorable lipid profiles.13PubMed. Genetic association of the CCR5 region with lipid levels in at-risk cardiovascular patients
For rheumatoid arthritis, delta 32 carriers showed reduced disease susceptibility, less joint erosion, and lower inflammatory markers over time.14PubMed Central. Negative association of the chemokine receptor CCR5 d32 polymorphism with systemic inflammatory response, extra-articular symptoms and joint erosion in rheumatoid arthritis The picture is less clear for other autoimmune conditions. A meta-analysis found no significant link between delta 32 and lupus risk.15Egyptian Journal of Medical Human Genetics. A meta-analysis on association between chemokine receptor 5 delta32 polymorphism and risk of systemic lupus erythematosus And while some data suggest a slightly protective role in multiple sclerosis, the findings have been inconsistent across studies.16PubMed. CCR5Δ32 – A piece of protection in the inflammatory puzzle of multiple sclerosis susceptibility
The overall meta-analysis for atherosclerotic disease as a whole did not find a significant association in European populations, though there was a signal in Asian subgroups.17PubMed Central. Association between chemokine receptor 5 (CCR5) delta32 gene variant and atherosclerosis: a meta-analysis of 13 studies The honest reading of the cardiovascular evidence is that delta 32 likely confers some anti-inflammatory benefit, but the size of that benefit and its clinical significance remain debated.
Brain Recovery and Neurological Effects
One of the more surprising findings about CCR5 has come from neuroscience. In a large clinical cohort of stroke patients, those who naturally carried the delta 32 mutation recovered more of their neurological and cognitive function than non-carriers.18PubMed Central. CCR5 Is a Therapeutic Target for Recovery after Stroke and Traumatic Brain Injury The proposed explanation involves two mechanisms: reducing the inflammatory damage that follows a stroke and promoting the regrowth and stabilization of neural connections. Animal studies have shown that blocking CCR5 stabilizes dendritic spines (the tiny protrusions on neurons that receive signals) during the critical window of post-stroke damage and triggers new wiring between brain regions.19PubMed Central. CCR5-Δ32 polymorphism: a possible protective factor for post-stroke depressive symptoms
CCR5 is now recognized as playing a broader role in neuroinflammation, synaptic plasticity, and cognitive function beyond stroke alone.20PubMed. CCR5 as a key modulator in neurocognitive disorders Drug companies have taken notice. Maraviroc, an existing HIV drug that blocks CCR5, is being explored as a potential treatment for stroke recovery and traumatic brain injury. If those trials succeed, knowing your CCR5-delta32 status could eventually become relevant to your neurological care, not just your infectious-disease risk.
The Mortality Question
In 2019, a widely reported study used UK Biobank data from over 400,000 people of British ancestry and estimated a 21% increase in all-cause mortality for homozygous delta 32 carriers.21PubMed Central. CCR5-∆32 is deleterious in the homozygous state in humans The finding made headlines and raised concerns about the safety of gene-editing approaches that aimed to knock out CCR5. However, the study was subsequently challenged on methodological grounds. Critics identified issues with how the UK Biobank genotyping data was handled, and attempts to replicate the mortality finding with corrected data failed to confirm the original result. The authors themselves published a correction acknowledging problems with the analysis.
The episode is a useful reminder that a single study, even a large one, can be misleading when there are technical pitfalls in the data. The West Nile vulnerability and the cardiovascular and stroke-recovery data paint a picture of real tradeoffs, but the sweeping claim that homozygous carriers die younger across the board remains unproven. If you test homozygous, this should not be a source of alarm about your lifespan.
The Berlin Patient and What CCR5 Means for HIV Cures
The most dramatic real-world demonstration of delta 32’s power came in 2008, when an HIV-positive man with leukemia received a stem-cell transplant from a donor who was homozygous for the deletion. He stopped taking antiretroviral drugs at the time of transplant and remained free of detectable HIV for years afterward, with even the most sensitive tests unable to find replication-competent virus.22PubMed Central. CCR5 Targeted Cell Therapy for HIV and Prevention of Viral Escape23PubMed. Long-term control of HIV by CCR5 Delta32/Delta32 stem-cell transplantation Known as the “Berlin Patient,” this case became the first accepted cure of HIV.
Since then, additional patients with blood cancers and HIV have been cured through the same approach: transplanting stem cells from homozygous delta 32 donors.24PubMed Central. Curating evidence for a cure of HIV-1 infection by hematopoietic stem cell transplantation The procedure is too risky and complex to serve as a general HIV treatment. It requires chemotherapy or radiation to destroy the patient’s own immune system first, and compatible homozygous donors are rare. But these cases proved the concept: remove CCR5 from a person’s immune cells, and HIV loses its foothold.
That proof of concept has driven interest in using gene-editing tools like CRISPR-Cas9 to knock out CCR5 in a patient’s own cells, eliminating the need for a matched donor altogether.25PubMed Central. A CRISPR-Cas Cure for HIV/AIDS The idea gained notoriety in 2018 when a Chinese researcher used CRISPR to edit the CCR5 gene in human embryos, resulting in the birth of twin girls. The experiment was widely condemned as premature, ethically reckless, and scientifically unnecessary, since the father’s HIV could have been managed through standard means.26PubMed Central. CCR5-Δ32 biology, gene editing, and warnings for the future of CRISPR-Cas9 as a human and humane gene editing tool The case underscored both the therapeutic promise of CCR5 disruption and the dangers of deploying it without fully understanding the consequences, especially the West Nile vulnerability and the still-uncertain effects on inflammation and brain function.
Practical Reasons to Find Out Your Status
For most people, knowing your delta 32 status is a matter of curiosity rather than urgent medical necessity. Modern antiretroviral therapy is so effective that HIV-positive people who take their medication can achieve undetectable viral loads and a normal lifespan, regardless of their CCR5 genotype. Pre-exposure prophylaxis (PrEP) is highly effective at preventing HIV transmission in the first place. Knowing you carry one copy of delta 32 does not change the recommendation to use PrEP if you are at risk.
That said, there are scenarios where the information becomes more than academic. If you are living with HIV and develop a blood cancer that requires a stem-cell transplant, your medical team will want to know whether a homozygous delta 32 donor could serve double duty, treating both the cancer and potentially curing the HIV. If you are a potential stem-cell or bone-marrow donor, your delta 32 status could make you an exceptionally valuable match for an HIV-positive recipient. And as CCR5-targeted therapies for stroke recovery and other neurological conditions advance through clinical trials, your genotype could become relevant to treatment planning in ways that are hard to predict today.
If you decide to get tested, a genetic counselor can help you understand the result in context. A single copy of delta 32 is not a shield against HIV. Two copies confer strong but not absolute resistance, since rare strains of HIV can use a different receptor to enter cells. And both genotypes carry tradeoffs in other areas of health. The test itself is simple. Interpreting what it means for your life takes a bit more nuance.