TMPRSS2 variants and their susceptibility to COVID-19: focus in East Asian and European populations.

The manifestation of the COVID-19 varies from absence of symptoms to Severe Acute Respiratory Syndrome. The epidemiological data indicate that infection and mortality rates are greater in European populations in comparison with eastern Asians. To test if epidemiological patterns may be partly determined by human genetic variation, we investigated, by exomic and databank analyses, the variability found in the TMPRSS2 gene in populations from different continents, since this gene is fundamental to virus access into human cells. The functional variants revealed low diversity. The analyses of the variation in the modifiers of gene expression indicate that the European populations may have much higher levels of pulmonary expression of the TMPRSS2 gene and would be more vulnerable to infection by SARS-CoV-2. By contrast, the pulmonary expression of the TMPRSS2 may be reduced in the populations from East Asia, which implies that they are less susceptible to the virus infection and, these genetic features might also favor their better outcomes. The presented data, if confirmed, indicates a potential genetic contribution of TMPRSS2 to individual susceptibility to viral infection, and might also influence COVID-19 outcome.