Although both IgM and IgG anti-ACE2 have been observed in COVID-19 patients, it is IgM anti-ACE2 that are associated with severe disease and appear late in the disease course around day 8–10 of hospitalisation (Casciola-Rosen et al. 2020; Rodriguez-Perez et al. 2021). The gene discussed is ACE2; the disease is COVID-19.