How genes affect COVID-19 risk
Scientists are still trying to work out what makes one person’s coronavirus infection just a bad cough, and another person’s a life-threatening hospital visit. There are plenty of theories relating to your age, sex, health, and more. But what about your genes, such the gene for ACE discussed earlier? How much do they explain? And, like some have theorised, could this be why certain minority ethnic groups are disproportionately going to hospital with this disease? According to Ewan Birney, that’s unlikely. He’s director of the European Bioinformatics Institute, helping gather coronavirus patient DNA…
Ewan - Actually, most of the variation about whether you're infected with the virus will be due to your exposure, but some, perhaps of whether you progress or whether in hospital you have a mild form of the disease or severe form of the disease, those may well have genetic factors contributing to the variation that we see.
Phil - And do you have an idea for this coronavirus of how big a role genetics might play?
Ewan - No, we don't really. There's been some initial work using some twin studies that says that there's some evidence that there's going to be a genetic component, and our experience of of many other previous studies would argue there'll be some aspect. For me. I think in particular between mild and severe disease is going to be our most fruitful area to look at. But we're not, we can't say that for sure in many ways one has to collect the data set and do the analysis before one can be sure. The very early genetic analysis is not showing much variance being contributed by genetics, but we just don't have the sample size to be sure that that's the full story. We need to wait until we have more cases coming through the system.
Phil - If you do find something, what's the point? What can you actually do with that?
Ewan - Yeah, potentially it can point us to parts of the genome where different individuals in the population vary and if we're lucky that part of the genome is in a pathway that we've already got a drug for. That would be our best result. Now if we find something in the genome that there isn't a drug, there is a possibility of making a new drug that is a long, long road, though. A final possibility is that there are genetic components which are big enough that they really show the difference between different individuals in a way that we can actually use in terms of saying well you're very much at risk and you're not. Now I actually don't think that's going to be a likely outcome of the genetics: tends to be that genetics is very complicated, but it is a possibility
Phil - If you do end up finding patterns, are they likely to be with, you know, everyone or are they going to be patterns in specific groups of people or what?
Ewan - Human genetics is very mixed and very messy and so they're likely to be weak and distributed across all humans on the planet. That's the way most human genetics works out. It's important to realize that although we, in society, we have a lot of casual use of self identified ethnic groups. So if you're presented with a form where you're asked to tick who you are, whether you're a European American or an African American or a white British or white Irish or these other terms, most people feel confident about ticking those boxes. That process of ticking boxes is less aligned to genetics than people's intuition thinks. So it's unlikely that there's going to be big differences between these self identified ethnic groups. Now you might be aware that it's reasonably clear both in the UK and the US that many people in minority ethnic groups, African Americans in the US and Afro-Caribbeans and South Asians in the UK, seem to be disproportionately represented in hospitalizations of Covid-19. But what you have to remember is two things. Firstly, the biggest outbreaks are happening in dense urban city centres, London, New York, and these spaces which have a much higher level of of these groups. And secondly, many of the things that we know are involved with causing severe disease such as type two diabetes and obesity, cardiovascular issues, are related to socio-economic status, which is related to how much money you have. And that is distributed in a very skewed way in our society. So I'm relatively confident that there is not a big genetic component explaining the observed differences we see of ethnic group labels with Covid-19.