ACE2 is cleaved by TMPRSS2 as a secondary function of the serine protease at at Arginine 697 to 716 to further facilitate viral entry. This suggests that populations such as non-Finnish Europeans that carry ACE2 polymorphisms including p.Arg708Trp, p.Arg710Cys, p.Arg710His, and p.Arg716Cys may have milder COVID-19 symptoms. These mutations cause ACE2 to lose their cleavage sites, so TMPRSS2 cannot cleave the enzyme in the same way and causes the receptor to change its conformation.