Future studies to resolve the roles and origins of anti-ACE2 IgM and IgG in COVID-19 severity and vasculopathy will likely provide additional insights into both underlying mechanisms and rational application of novel therapeutics (e.g., calcineurin inhibitors, which appear to decrease severity and mortality in the severe MDA5-associated phenotype; ref. 32). The gene discussed is ACE2; the disease is COVID-19.