PNPLA3 GG Genotype and Carotid Atherosclerosis in Patients with Non-Alcoholic Fatty Liver Disease

BACKGROUND AND AIM To evaluate if the presence of carotid atherosclerosis in patients with NAFLD, could be related to gene variants influencing hepatic fat accumulation and the severity of liver damage. METHODS We recorded anthropometric, metabolic and histological data(Kleiner score) of 162 consecutive, biopsy-proven Sicilian NAFLD patients. Intima-media thickness(IMT), IMT thickening(IMT≥1 mm) and carotid plaques(focal thickening of >1.3 mm at the level of common carotid artery) were evaluated using ultrasonography. IL28B rs12979860 C>T, PNPLA3 rs738409 C>G, GCKR rs780094 C>T, LYPLAL1 rs12137855 C>T, and NCAN rs2228603 C>T single nucleotide polymorphisms were also assessed. The results were validated in a cohort of 267 subjects with clinical or histological diagnosis of NAFLD from Northern Italy, 63 of whom had follow-up examinations. RESULTS Carotid plaques, IMT thickening and mean maximum IMT were similar in the two cohorts, whereas the prevalence of diabetes, obesity, NASH, and PNPLA3 GG polymorphism(21%vs.13%, p = 0.02) were significantly higher in the Sicilian cohort. In this cohort, the prevalence of carotid plaques and IMT thickening was higher in PNPLA3 GG compared to CC/CG genotype(53%vs.32%, p = 0.02; 62%vs.28%, p<0.001, respectively). These associations were confirmed at multivariate analyses (OR2.94;95%C.I. 1.12-7.71, p = 0.02, and OR4.11;95%C.I. 1.69-9.96, p = 0.002, respectively), although have been observed only in patients <50years. Also in the validation cohort, PNPLA3 GG genotype was independently associated with IMT thickening in younger patients only (OR: 6.00,95%C.I. 1.36-29, p = 0.01), and to IMT progression (p = 0.05) in patients with follow-up examinations. CONCLUSION PNPLA3 GG genotype is associated with higher severity of carotid atherosclerosis in younger patients with NAFLD. Mechanisms underlying this association, and its clinical relevance need further investigations.