NUDT15*7 is assigned no function based on moderate evidence. Patients carrying a NUDT15*7 allele tolerate lower doses of thiopurines (28659275 , 32873882 , 32221476 ). An in vitro study using a bacterial expression system found that NUDT15.7 enzymatic activity was undetectable and NUDT15.7 exhibited decreased protein thermostability compared to NUDT15.1 (28659275). An additional in vitro study expressed NUDT15*7 in HEK293 cells and found that the protein was expressed at similar levels to NUDT15.1, but cells were significantly more sensitive to thiopurine treatment (32094176). Nine out of nine variant effect predictors tested by CPIC staff predict that the NUDT15*7-defining SNV, c.101G>C (p.R34T), impairs protein function.