I148M variant of PNPLA3 increases the susceptibility to non-alcoholic fatty liver disease caused by obesity and metabolic disorders.

BACKGROUND: The patatin-like phospholipase 3 (PNPLA3) rs738409 gene polymorphism is an important genetic determinant of non-alcoholic fatty liver disease (NAFLD). However, the associations between liver fat and metabolic traits in rs738409 G allele carriers and the allelic influence on this association have not been fully studied.

AIM: To investigate the influence of the PNPLA3 gene polymorphism on the association of liver fat with serum metabolic factors and carotid atherosclerosis.

METHODS: Liver fat was measured by quantitative ultrasound in 4300 subjects in the Shanghai Changfeng community and analysed for its association with obesity and metabolic factors in individuals with the PNPLA3 CC, CG and GG genotypes.

RESULTS: Non-alcoholic fatty liver disease occurred in 37.9% and 28.8% of the subjects with the GG and CC genotypes respectively (P < 0.001). Liver fat was significantly associated with body mass index, waist circumference, serum triglycerides, high-density lipoprotein cholesterol, fasting blood glucose and insulin in the PNPLA3 rs738409 G allele carriers (P < 0.001). Compared with the CC homozygotes, the GG homozygotes presented higher liver fat and liver fibrosis scores despite their better metabolic status (comparison of regression line slopes, P < 0.05). An increase in liver fat was accompanied by a significant increase in the average and maximum carotid intima-media thickness in subjects with the PNPLA3 CC genotype but not in those with the GG genotype.

CONCLUSIONS: PNPLA3 rs738409 G allele carriers were found to be more susceptible to the metabolic-related hepatic steatosis, and developed NAFLD and liver fibrosis despite presenting relatively better metabolic statuses and lower risks for carotid atherosclerosis.