N-acetyltransferase and cytochrome P450 2E1 gene polymorphisms and susceptibility to antituberculosis drug hepatotoxicity in an Indian population.
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Date
2013-09
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Abstract
Background. Antituberculosis drug hepatotoxicity (ATDH)
is common in India. Isoniazid, a constituent of most antituberculosis
drug regimens, is metabolized by N-acetyltransferase
(NAT2) and cytochrome P450 2E1 (CYP2E1) enzymes. We
therefore studied the association of some single-nucleotide
polymorphisms (SNPs) in these enzyme genes with ATDH.
Methods. Allelic and genotypic frequencies at three SNP
loci in the NAT2 gene (rs1799929, rs1799930 and
rs1799931) and one locus (rs2031920) in the CYP2E1 gene
were studied using restriction fragment length polymorphism in
33 patients who developed ATDH following an isoniazidcontaining
antituberculosis drug regimen and 173 healthy
blood donors. After confirming adherence of the control data
to the Hardy–Weinberg equilibrium model, genotype and allele
frequencies in the two groups were compared.
Results. For SNP rs1799930 in the NAT2 gene, 7
(21%), 21 (64%) and 5 (15%) patients, and 93 (54%), 62
(36%) and 18 (10%) controls had GG, GA and AA
genotypes, respectively (p=0.003; odds ratio [OR] for GA
v. GG=4.50 [95% CI 1.80–11.22] and for AA v. GG=3.69
[1.05–12.93]). Allele frequency for G nucleotides for this
SNP was 0.53 among patients and 0.72 among controls (OR
2.24 [1.31–3.84], p=0.007). The allele and genotype
frequencies of the other NAT2 SNPs and the CYP2E1 SNP
showed no significant difference between cases and controls.
All the 33 patients and 151 (87%) of 173 controls had
mutant allele at one or more of the three NAT2 SNP loci
(p=0.03). The presence of two or more mutant alleles, a
marker of slow acetylator status, was more frequent in patients
(23/33 [70%]) than in controls (73/173 [42%]; OR 3.23
[95% CI 1.45–7.19], p=0.004). Conclusion. In India, the risk of ATDH is increased in
persons with ‘A’ allele at SNP rs1799930 in the NAT2 gene,
but is not associated with rs2031920 polymorphism in the
CYP2E1 gene.
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MISHRA SWAPNIL, DASCHAKRABORTY SUNILBARAN, SHUKLA PALLAVI, KAPOOR PRERNA, AGGARWAL RAKESH. N-acetyltransferase and cytochrome P450 2E1 gene polymorphisms and susceptibility to antituberculosis drug hepatotoxicity in an Indian population. National Medical Journal of India. 2013 Sept-Oct ; 26 (5): 260-265.