Targeted and unbiased metabolomic approaches have identified low serum levels of high-density lipoprotein (HDL cholesterol) and apolipoprotein-A-I (ApoA-I) as strong predictive factors of severe forms of COVID-19 (Sun et al., 2020; Begue et al., 2021; Hilser et al., 2021). The gene discussed is APOA1; the disease is COVID-19.