NAT2*47 is assigned decreased function based on limited evidence. NAT2*47 is characterized by the core SNVs c.191G>A (p.R64Q), c.683C>T (p.P228L), and c.803G>A (p.R268K). c.803G>A (p.R268K) defines NAT2*4, formerly considered the reference allele, which has repeatedly shown increased function in vivo and in vitro. Published in silico modeling predicts that c.683C>T (p.P228L) impairs protein function based on the exposure of hydrophobic residues that may facilitate protein aggregation and/or targeted protein degradation (19909761). However, two out of nine variant effect predictors tested by CPIC staff predict that c.683C>T (p.P228L) impairs protein function. c.191G>A (p.R64Q, defining NAT2*14) has repeatedly shown decreased NAT2 function in numerous in vivo and in vitro studies. Six out of nine variant effect predictors tested by CPIC staff predict that c.191G>A (p.R64Q) impairs protein function. Published in silico modeling predicts that c.191G>A (p.R64Q) decreases protein stability and hinders electrostatic interactions (18680467). A NAT2 phenotyping study identified one patient with the genotype NAT2*5/*47 and this individual was classified a "slow acetylator" (24533708). In this study, slow acetylators exhibited lower metabolic ratios of acetyl-INH/INH that were statistically significant compared to both rapid and intermediate acetylators, as well as an increased INH half-life, increased INH AUC values, and decreased INH CL/F values (24533708). NAT2*47 is assigned decreased function based on the function of c.191G>A (p.R64Q). Despite this, it remains unknown whether there are any combinatorial effects associated with c.683C>T and c.191G>A