Genetic variations in the human severe acute respiratory syndrome coronavirus receptor ACE2and serine protease TMPRSS2

AimsThe recent emergence of novel, pathogenic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a global health emergency. The coronaviral entry requires the spike (S)-protein for attachment to the host cell surface, and employs human angiotensin-converting enzyme 2 (hACE2) for entry and transmembrane protease serine 2 (TMPRSS2) for S-protein priming. Although coronaviruses undergo evolution by mutating themselves, it is also essential to know the host genetic factors. Here, we describe the single nucleotide variations (SNVs) in human ACE2and TMPRSS2.MethodsThe genetic variants derived from five population-sequencing projects were classified by variant type, allele frequency (AF), ethnic group and estimated pathogenicity. The SNVs in SARS-CoV-2/hACE2 contact residues were investigated. The genetic variability was normalised using non-linear regression and the total number of SNVs was estimated by the derived formulas.ResultsWe detected 349 and 551 SNVs in ACE2and TMPRSS2, respectively, in a total of 156 513 individuals. The vast majority (>97%) of the SNVs were very rare (AF <0.1%) and population-specific, and were computationally estimated to be more frequently deleterious than the SNVs with high AF. These SNVs were distributed throughout the coding regions; some ACE2 variants were located in the SARS-CoV-2/hACE2 contact residues, with a hemizygous state occurring in males. Using regression analysis, the total numbers of genetic variations in ACE2and TMPRSS2were 1.1×103and 1.5×103, respectively, for a population of one million people.ConclusionThe majority of SNVs in ACE2and TMPRSS2are rare, population-specific and deleterious, and a multitude of very rare SNVs may explain different susceptibility to SARS-CoV-2.