CYP2A6 Polymorphisms May Strengthen Individualized Treatment for Nicotine Dependence

Table 2

Estimates of CYP2A6 gene variants nicotine metabolizer activities.

Metabolizer groups	Estimates enzymatic activities	Genotype descriptions
Normal metabolizer (NM)	100% nicotine metabolism	No loss of alleles function detected CYP2A6^*1A
Slow metabolizers (SM)	(1) Less than 50% of nicotine metabolism activities	Less than 1/0 allele loss-of-function.; Examples: CYP2A^*2 & ^*4
	(2) Nearly 75% of nicotine metabolism activities	1 allele loss-of-function; Examples: CYP2A^*9 & ^*12

Note. In general, gene variant decreases enzymatic activities due to their loss-of-functions [3, 22].