The Reason I’m Alive
For a variety of reasons I’ve always considered myself to have been exceptionally lucky, but last week I got news that increased still further the extent of this sense of good fortune. I hesitated before putting anything about this on here because it is rather personal and there are details I’m going to leave out about how I came by the information.
Over a month ago I posted some thoughts about the TV series It’s A Sin based on my own experiences back in the 1980s. That post ended with this:
… a question that often troubles me returned once again to my mind: why am I still alive, when so many people I knew back then are not?
In response to this a former colleague of mine suggested I get my DNA sequenced to see if I had any innate resistance to HIV infection. I wasn’t sure how to go about doing this but one of the advantages of having worked in several different universities is that I know people in several bioscience and biomedical departments, including people who work on the data science aspects of genetics. After emailing around for advice I eventually ended up talking to a very distinguished scientist in that field to whom I explained the situation.
Since I didn’t really want to have a copy of my entire genome sequence – that’s a lot of data most of which I wouldn’t understand – but just wanted to know the answer to one question it seemed a waste of money to have this done commercially (although at around €1000 it’s not enormously expensive). Instead a plan emerged in which I would offer my (suitably anonymized) DNA as part of a scientific study in return for the small piece of information I wanted.
After a few days I received a kit for taking oral swabs, a medical questionnaire and quite a lot of paperwork to do with ethical considerations and data protection. I sent everything back by return post. Last week the results came back. There was some general info about my genetic make-up – which shows a considerable dollop of Scandinavian ancestry – alongside the answer the question I had asked.
The full DNA sequence of my genome reveals that I have the CCR5-Δ32 genetic mutation. Not just that. I have it twice (i.e. it’s homozygous), which means that I inherited it from both parents.
Of order 1% of the European population has this mutation, which is thought to have arisen in a single Scandinavian individual at some stage during the Viking era and subsequently propagated through mainly Northern Europe where about 10% have one copy, and about 1% have two.
Here is a map of the geographical distribution in Europe (from this paper) :
It’s nowhere near as prevalent in Asia or African populations.
So what does this mean?
Heterozygotic CCR5-Δ32 (i.e. one mutated gene) confers some protection against HIV infection but the homozygotic CCR5-Δ32 mutation involving both copies confers virtually total immunity. I was terrified of AIDS in the 1980s but it turns out I was immune all the time without knowing it. This explains why to my great surprise the HIV test I took in the 1980s came back negative despite my sexual history and behaviour.
As a friend told me when I passed this news on: “you’re a f**king lucky bugger”. Indeed I am. I already considered myself to have been very lucky but this absolutely takes the biscuit.
P.S. My immediate “reward” for having this genetic peculiarity is to take part in further scientific study on it, which I am of course very happy to do.
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In the Dark 
February 27, 2021 at 11:18 am
According to the same article, there seem to be some potential costs:
February 27, 2021 at 11:20 am
Yes, I understand one of the topics in the study I referred to is the possible connection between this mutation and inflammatory illnesses.
February 27, 2021 at 11:26 am
Does it therefore make a person more susceptible to e.g. arthritis? I believe you suffer from this?
February 27, 2021 at 11:29 am
I think that is one of the possibilities under investigation. Rheumatoid arthritis is very poorly understood but does involve the immune system.
March 3, 2021 at 9:57 pm
It is reported on recent news that more than 4% of the people in the Republic of Congo have natural immunity against the AIDS virus.
March 3, 2021 at 10:00 pm
Interesting! Might be a different genetic factor.
February 27, 2021 at 1:43 pm
So it seems that the Vikings really did go south along the great rivers of Russia, a claim which is disputed by some. Also, the ‘Normans’ were Northmen who picked up Catholicism in Northern France and were the driving force behind the Crusades, getting all over the eastern Mediterranean (although the prevalence of this gene in Israel is clearly due to 20th century Jewish migration; it would be interesting to see the statistics for Gaza and the West Bank, which are Arab).
On the other hand, I might be indulging in circular logic, if the evidence for a Norse origin of the gene is what I have just stated…
It helps to be from the north-east, which took the full brunt of the Viking raids!
February 27, 2021 at 1:56 pm
Although I was born in the North-East not all my immediate family history is from there so it’s not as simple as that!
February 27, 2021 at 4:07 pm
Understood!
Continuing my theme nevertheless, the Byzantines had an elite unit, the Varangian Guard which bodyguarded the Emperor, consisting of Vikings (once they had taken up Christianity) and then Normans. King Harald Hardrada of Norway, who died in an attempt to invade England days before William the Conqueror’s success, had served in it. And earlier, the Vikings has sailed up the Seine under Rollo and sacked Paris.
I should have added that the Jews who brought this gene to Israel had picked it up most likely from rape at the hands of Europeans.
Is it known *how* this gene protects against HIV?
February 27, 2021 at 5:19 pm
Yes, I believe it is quite simple as these things go. The HIV virus enters a CD4 immune cell via the CCR5 co-receptor which usually sticks out from the cell and allows the virus to bind to it. The mutation causes the CCR5 to be smaller than usual and no longer sit outside of the cell. This closes the door on the virus which is unable to enter these cells.
February 27, 2021 at 6:05 pm
It’s interesting that the numbers for Ireland are just as large as those for Denmark. Data from Sweden are not in the figure I showed but it is believed that Sweden has the highest fraction in Europe of the delta-32 mutation.
February 27, 2021 at 5:23 pm
And no mutation of HIV, which mutates like blazes, has got round that?
I’ve been educating myself as best I can on the difference between the various SARS-CoV-2 vaccines, and also trying to read the literature on its origins based on sequencing. We physicists have it easy!
February 27, 2021 at 5:55 pm
I think it must be such a basic part of the way HIV works that no mutation has succeeded in circumventing it. It is easy to image how the mutation also affects the ability of immune cells to deal with other things though…
By the way here’s an article about genetic immunity in the context of both HIV and SARS-COV-2.
https://www.bbc.com/future/article/20210219-the-covid-resistant-patients-e-the-viruss-weak-spots
February 27, 2021 at 10:01 pm
Some were sensible enough to go south; they got round Spain into the Mediterranean and their ships were spotted by Charlemagne, who rightly saw trouble ahead. This according to his biographer one generation later, Notker the Stammerer.
April 19, 2021 at 10:18 pm
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June 9, 2022 at 4:56 pm
Hello, I found this blog entry by chance, doing a bit of research on this Delta32CCR5 mutation. One of my siblings (and our dad) were found (by both 23andMe, and Family Tree DNA) to be Delta32 heterozygotes; while the rest of our siblings (and our mom) were all regular ‘wild-type/wild-type’ for CCR5. Apparently dad passed the one mutated CCR5 allele copy to just one sibling, of 3. Just wondering, if I may, what your life health experiences have been like with regard to other potentially infectious diseases ranging from, say, influenza(s) to SARS-Cov2 during the pandemic. I’ve read some papers which seem to indicate this mutation may help for example with Sars-cov2 by, if anything, possibly dampening or tamping down the body’s excessive inflammatory response (e.g., the ‘cytokine storm’) which is actually what caused much of the mortality and hospitalization particularly during the 2020- late 2021 phases (Alpha, ‘beta’, ‘delta’, etc, prior to omicron). CCR5 blocker drugs like Leronlimab were used with some success I believe particularly during the earlier phases. With regard to influenza, papers have been contradictory at times or sample sizes seem small, etc, but talking to a couple of Δ32 heterozygotes (and one actual Δ32 homozygote) from 23andMe, they all claimed to have had minimal issues with influenza or other such things in their lives. The homozygous individual was of the age where he was given smallpox vaccination as a child, and he related that there was some issue with it where it didn’t seem to ‘take’ or had to be re-administered or something such as that. Then later I read that one of the possible reasons for the mutated Δ32 allele surviving at a steady though pretty low rate among Europeans in particular was possibly because of such a long time their ancestors went through of generation to generation smallpox exposure, and that Δ32 hetero- and homozygotes may have had a survival or maybe even initial infection protection advantage against smallpox, relative to double wild-types (double-normals). Anyway, very interesting, thanks.
June 9, 2022 at 8:40 pm
Thanks for your comment. I am intrigued by your comment that this mutation may help against Covid as, unlike most of my colleagues, I haven’t contracted it at all. I don’t think I’ve ever had a serious dose of influenza either…
June 10, 2022 at 2:51 am
For example, https://pubmed.ncbi.nlm.nih.gov/34913355/
https://pubmed.ncbi.nlm.nih.gov/33728925/
(preprint): https://www.medrxiv.org/content/10.1101/2020.11.02.20224659v1
June 10, 2022 at 6:04 pm
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August 7, 2024 at 11:01 am
I don’t know whether I have this mutation, but I do have the Hemophilia A one. This with the eighties and blood products were dangerous times, but Norway was lucky twice, not only have one in six some protection as seen in the map here, but the doctor(s) at the Hemophilia association, when noticing that blood products gave hepatitis non A non B as it was called at the time, instituted a policy where the blood from donors was not mixed in big vats as was usual in other countries, and had six donors to one dose of medicine. The rates of HIV for hemophiliacs with severe hemophilia in Norway were one in ten, whereas in, say, Sweden it was seven in ten.
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