FAS and COVID-19: However, this study has some limitations, including the evaluation of only two polymorphisms in the FAS gene and two polymorphisms in the FASL gene, but there are other polymorphisms in these genes that need to be evaluated in COVID-19; this study did not evaluate other components of the apoptosis cascade, since multiple components are involved in this process, and variations in other genes may influence the intensity of apoptosis activation.