A single individual determined to carry three copies of CYP2A6 was assumed to be heterozygous for a CYP2A6*1X2 duplication allele. The six individuals determined to carry only one copy of the gene were assumed to be heterozygous for a CYP2A6*4 deletion allele. Using 189 subjects and 8 variants, PHASE software predicted 11 haplotypes (Table 1). The most likely diplotypes were predicted with a probability of >0.97 for all subjects. Consistent with reported allele frequencies, homozygotes for the *1B 3′ gene conversion were also homozygous for the G allele at rs4803381 (−1013), the A allele at rs61663607 (−745), and the G allele at rs1137115 (+51) in all but one individual (n=1/20 subjects); the single exceptional individual heterozygous at all three polymorphic loci was considered a heterozygote for the *1B12 allele [24]. One heterozygote for the *1B 3′ gene conversion (n=1/81) was also a homozygote for the A alleles at both rs4803381 (−1013) and rs61663607 (−745), and a homozygote for the G allele at rs1137115 (+51) and was therefore considered a heterozygote for the *1B7 allele [24].
