NAT2*44 is assigned uncertain function based on inadequate evidence. NAT2*44 is characterized by the core SNV c.403C>G (p.L135V). There is no experimental evidence describing function for c.403C>G (p.L135V). Published in silico modeling predicts that c.403C>G (p.L135V) does not alter NAT2 protein function (19909761). Similarly, eight out of nine variant effect predictors tested by CPIC staff predict that c.403C>G (p.L135V) is neutral/tolerated for NAT2 protein function. The limited clinical data available for NAT2*44 was not sufficient to influence the allele clinical functional status (24444407). Additionally, a NAT2 phenotyping study identified a patient with the genotype NAT2*5/*44, however this individual was excluded from phenotype analysis (28959610).