NAT2*29 is assigned decreased function based on moderate evidence. The NAT gene nomenclature committee has historically assigned acetylation activity to alleles as either "rapid" or "slow", classifying the NAT2*29 allele as "slow" . Under the CPIC allele function terminology, slow acetylation alleles are categorized as "Decreased Function". NAT2*29 is characterized by the functional SNVs c.191G>A (p.R64Q, defining NAT2*14) and c.341T>C (p.I114T, defining NAT2*5) which have both repeatedly shown decreased NAT2 N-acetylation in numerous in vivo and in vitro studies. A NAT2 phenotyping study showed that an individual genotyped as NAT2*14/*29 exhibited decreased acetylation of dapsone, with values below the cut-off value used to discriminate phenotypic rapid from slow acetylators (10762005). An in vitro study using a bacterial expression system found that NAT2*29 exhibits decreased thermostability and decreased N-acetyltransferase activity toward sulfamethazine and isoniazid (28523442 ). An additional in vitro study showed that NAT2*5 (which contains the core SNV c.341T>C, p.I114T) is subjected to enhanced protein degradation by the proteasome (15564878). Thus, NAT2*29 would presumably be degraded in the same manner. Additionally, five and six out of ten variant effect predictors tested by CPIC staff predict that c.341T>C (p.I114T) and c.191G>A (p.R64Q) impair protein function, respectively. While c.191G>A and c.341T>C are both definitively attributed to decreased function individually, the combinatorial effects of having both variants present in the same allele are uncertain.