Relatively high occurrence of the CYP2R1 rs10741657 G variant in different populations, reproducible association with decreased 25OHD levels and observed relationship with severe COVID-19 in our group of patients, gives a solid ground for future studies to examine relationship of this CYP2R1 variant with the clinical course of COVID-19 in other populations. The gene discussed is CYP2R1; the disease is COVID-19.