NADSYN1 and COVID-19: Therefore, we evaluated genetic determinants of vitamin D (DHCR7/NADSYN1 rs12785878, GC rs2282679, CYP2R1 rs10741657, VDR rs2228570), zinc (PPCDC rs2120019) and selenium (DMGDH rs17823744) as risk factors for severe forms of COVID-19.