NUDT15*16 is assigned uncertain function based on inadequate evidence. An in vitro study expressed NUDT15*16 in HEK293 cells and found that NUDT15.16 protein levels were significantly decreased compared to NUDT15.1, and NUDT15*16 increased thiopurine sensitivity in cells (32094176). Seven out of nine variant effect predictors tested by CPIC staff predict that the NUDT15*16-defining SNV, c.88C>T (p.L30V), impairs protein function.