NUDT15*15 is assigned uncertain function based on inadequate evidence. An in vitro study expressed NUDT15*15 in HEK293 cells and found that NUDT15*15 protein levels were comparable to NUDT15*1 and NUDT15*15 had no effect on thiopurine sensitivity in cells (32094176). Five out of nine variant effect predictors tested by CPIC staff predict that c.467T>A (p.L156Q) impairs protein function.