COVID-19 has been in the top news for weeks now, discussed by both media outlets and social networks. It has literally infected the minds of most people living in society. For geneticists, the main interest lies in immunogenetics – in other words, people’s genetic resistance to various contagious diseases.
The fact is there are quite many SNPs, or single nucleotide polymorphisms, related to hereditary immunity factors. For example, there are SNPs connected to cytokines responsible for developing a local protective response in tissues that manifests itself as inflammation and results in swelling, reddening or pain.
There is also a polymorphism related to resistance to human immunodeficiency syndrome – specifically, in the CCR5 gene. This receptor can be mainly found on the surface of immune cells and is linked to chemokine, a low-molecular-weight protein that activates lymphocytes and helps to ‘recruit’ them to the location of an infection or inflammation. As HIV uses these particular receptors to penetrate cells, if a mutation occurs, the immunodeficiency virus can no longer use the receptor for its attacks.
Interestingly, people with this type of mutation are more commonly found in northern Europe – in Scandinavia, and our Pomors are among these people. Around 1% of Europeans carry this mutation in both binary chromosomes; another 18% of Europeans have this mutation in one of the binary chromosomes (so-called heterozygous mutation).
There was even a scandal involving this gene. In 2018, Chinese scientist He Jiankui announced that he used the CRISPR/Cas9 technology to modify the genome of embryos so that babies are born with polymorphism in the CCR5 gene. Two girls were born; one of them had both copies of the CCR5 gene modified, while in the other, only one of the genes was modified, which means she could still be infected with HIV. Their father was HIV positive.
He Jiankui was sentenced to almost two years in prison and a fine of RMB 500K because the experiment was held in violation of the law and crossed the line in terms of ethic/morality. But the fact remains that this gene and others had a polymorphism. They can have either a protective effect or bear the risk of the development of a disease.
The polymorphism can show a tendency towards, for instance, viral diseases (MBL2 or TLR3) or even risk (or resilience) to the SARS coronavirus (OAS1).
The mankind has seen many large viral disease outbreaks, and the panic that we are witnessing now shows the fear of the previous sad experience of counteracting dangerous viruses. I’m sure that the COVID-19 pandemic will give a boost to new research of human body’s genetic resistance to such viruses.
In fact, it is not that difficult to create a test to diagnose this genetic predisposition. It is also possible that such tests will be included in the diagnostics standards like a complete blood count or a kidney ultrasound. Sooner or later, this and other genetic tests will become routine even for newborns.
However, it is much more difficult to change the existing order than to create a system from scratch. The work to create genetic passports for all Russian citizens has only begun, so why not adding tests to diagnose genetic predisposition to viral diseases and developing relevant lifestyle recommendations? But even this decision will be made at the government level, the implementation will take years and millions of rubles. Private businesses are a different story: they are suffering huge losses because it is impossible to determine who should be isolated.
By Mikhail Zabotin, Director of Medical Education, Basis Genomic Group