Based on limited published evidence, NUDT4B is a nudix hydrolase that cleaves diphosphate groups from inositol polyphosphates (PP-InsP5, PP-InsP4, and [PP]2-InsP4), suggesting a role in signal transduction. It also hydrolyzes dinucleoside oligophosphates (Ap6A) and 5-phosphoribose 1-diphosphate. NUDT4B localizes to the cytoplasm and nucleus, exhibits bis(5'-adenosyl)-hexaphosphatase and diphosphoinositol-polyphosphate diphosphatase activities, and binds U8 snoRNA. Recent analysis identified NUDT4B as a disease-associated m7G-related gene with elevated expression in COVID-19 patients 1.