South Asian gene does not fully explain COVID-19 susceptibility

The following op-ed was written by Winston Morgan, B.S., Ph.D., FHEA, FRSB, professor of applied toxicology, equity, and inclusive practice at the School of Health, Sport and Bioscience at the University of East London in the United Kingdom.

A recent study suggests that a variant of a gene called LZTFL1 may explain why South Asians are more susceptible to COVID-19. This gene normally helps cells in the lungs respond to viral infections.

The variant is thought to be inherited from our Neanderthal ancestors and is found in more than 60% of South Asians and in 15% of Europeans and is almost absent in Black Africans and East Asians.

For scientists, particularly those with an interest in population genetics and molecular biology, this type of study is very exciting. Beyond the science, such discoveries are significant for everyone, as they could provide new diagnostics and treatments for COVID-19 and should be a cause for optimism generally.

Unfortunately, studies like these have other implications that can cause serious concerns in the communities most affected by these discoveries, particularly when the reporting is sensational.

I have spoken to South Asian friends of mine who are worried about what it could mean for them. They have to consider whether their genes really make them specifically vulnerable to COVID-19. In a pandemic-affected future, where COVID-19 could always be with us, what could this mean for things like life insurance if you have the genes in question?

This type of study also provides ammunition for those with a genetic determinist mindset, who want to divide us on the basis of race and ethnicity.

However, before anyone gets too excited, and despite the headlines, a closer look at the study tells a different story.

It makes many — as yet unproven — assumptions linking the existence of this variant to a series of cellular responses in the lungs following viral infection, which are necessary before any possibility of extra deaths in the affected populations.

To accept this explanation, we must also accept that this gene variant — which allegedly makes carriers more susceptible not just to COVID-19 but to coronaviruses in general, including influenza — is disproportionately found and then expressed in South Asians, leading to negative consequences.

Such a sequence of events is not fully supported by real-world evidence and throws up even more questions. The most obvious is that given the prevalence and pathogenicity of coronaviruses in shaping modern human history, how has the South Asian population survived and thrived so well today?

For example, we are often told that coronaviruses are the main reason New World populations were decimated once they came into contact with invading Europeans.

You would expect that for such a gene linked to this type of vulnerability to become so widespread in any population, it would have to be associated with an additional and obvious survival advantage in that population to counter the susceptibility to coronaviruses.

Presently, no such survival advantage has been identified, so perhaps the gene is not as lethal as the study suggests.

More importantly, why is there such a vast difference between the impact of COVID-19 on Bangladeshis and Indians, with 60% of both populations carrying the same variant of LZTFL1? Why are Black Africans who do not have the variant, as susceptible to the virus as the Bangladeshi population, and what is driving their susceptibility?

The problem with all these gene-based explanations for COVID-19 susceptibility — and with many other medical conditions — is that they conveniently shift the blame.

The blame lands on the populations already suffering [the] most, rather than focusing on the structural issues in our societies; these are the real drivers of the disproportionate deaths from COVID-19 linked to race and ethnicity.

However, this study could have something significant to contribute. It could help us understand why Neanderthals died out.

Could the presence of this gene variant in Neanderthals be a key driver for their extinction following a similar coronavirus pandemic thousands of years ago? This is a more compelling story.

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