PNPLA3 polymorphisms are associated with raised alanine aminotransferase levels in hepatitis C virus genotype 3

Hepatitis C virus (HCV) infection is one of the leading causes of end-stage liver diseases. This study aimed to determine the association between polymorphisms in interleukin 28B (IL28B), PNPLA3, toll-like receptor 7 (TLR7), nucleotide-binding oligomerization domain-containing protein 2 (NOD2) and retinoic inducible gene-I (RIG-I) and HCV genotype and clinical presentation in an Indian population.

A total of 500 patients with chronic HCV were enrolled in 19 centres across India. Genomic DNA was extracted from whole blood samples, and single nucleotide polymorphisms (SNPs) for IL28B, PNPLA3, TLR7, NOD2 and RIG-I genes were genotyped by real-time PCR using a TaqManSNP genotyping assay.

The mean age of the patients was 45 + 13 years, and the most common genotype observed was HCV genotype 3 (54%), followed by genotype 1 (24%). Although the allelic frequencies of TLR7, NOD2 and RIG-I were in significant disequilibrium in HCV patients compared with those in controls, the PNPLA3 polymorphism correlated significantly with higher viral load and alanine aminotransferase (ALT) levels in genotype 3 patients. Patients with PNPLA3 CG/GG genotypes, along with IL28B genotype CC, had higher levels of ALT than those with other genotypes.

These results indicate that PNPLA3 polymorphisms are associated with higher ALT levels in HCV genotype 3 patients in India and can help in identifying people who are at greater risk of developing HCV-associated liver diseases.