OBJECTIVE: Single-nucleotide-polymorphisms in PNPLA3-rs738409 and the TM6SF2-rs58542926, associated with metabolic-dysfunction-associated fatty liver disease (MAFLD), have been discussed as potentially protective for cardiovascular diseases. Therefore, we aimed to study the associations of PNPLA3/TM6SF2 variants with MAFLD and cardiovascular risk in a population-based sample of asymptomatic patients.
METHODS: The study cohort comprised 1742 patients of European decent aged 45-80 years from a registry study undergoing screening colonoscopy for colorectal cancer between 2010 and 2014. SCORE2 and Framingham risk score calculated to assess cardiovascular risk. Data on survival were obtained from the national death registry RESULTS: Half of included patients were male (52%, 59 ± 10 years), 819 (47%) carried PNPLA3‑G and 278 (16%) TM6SF2-T-alleles. MAFLD (PNPLA3‑G-allele: 46% vs. 41%, p = 0.041; TM6SF2‑T-allele: 54% vs. 42%, p < 0.001) was more frequent in patients harbouring risk alleles with both showing independent associations with MAFLD on multivariable binary logistic regression analysis. While median Framingham risk score was lower in PNPLA3‑G-allele carriers (10 vs. 8, p = 0.011), SCORE2 and established cardiovascular diseases were similar across carriers vs. non-carriers of the respective risk-alleles. During a median follow-up of 9.1 years, neither PNPLA3‑G-allele nor TM6SF2‑T-allele was associated with overall nor with cardiovascular mortality.
CONCLUSIONS: Carriage of PNPLA3/TM6SF2 risk alleles could not be identified as significant factor for all-cause or cardiovascular mortality in asymptomatic middle-aged individuals undergoing screening colonoscopy.

Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases, along with steatosis and non-alcoholic steatohepatitis (NASH), and is associated with cirrhosis and hepatocellular carcinoma. Candidate gene and genome-wide association studies have validated the relationships between NAFLD, NASH, PNPLA3, TM6SF2, and HFE. The present study utilized five polymorphisms in three genes: PNPLA3 (I148M and K434E) TM6SF2 (E167K), and HFE (H63D and C282Y), based on undocumented case−control studies in the Saudi Arabian population. A total of 95 patients with NAFLD and 78 non-NAFLD subjects were recruited. Genomic DNA was isolated, and polymerase chain reaction and Sanger sequencing were performed using specific primers for the I148M, K434E, E167K, H63D, and C282Y. NAFLD subjects were older when compared to controls and showed the significant association (p = 0.0001). Non-significant association was found between gender (p = 0.26). However, both weight and BMI were found to be associated. Hardy−Weinberg equilibrium analysis confirmed that H63D, I148M, and K434E polymorphisms were associated. Genotype analysis showed only K434E variant was associated with NAFLD and non-NAFLD (OR-2.16; 95% CI: 1.08−4.31; p = 0.02). However, other polymorphisms performed with NAFLD and NASH were not associated (p > 0.05), and similar analysis was found when ANOVA was performed (p > 0.05). In conclusion, we confirmed that K434E polymorphism showed a positive association in the Saudi population.

BACKGROUND: The present study investigates if common missense functional variants p.I148M and p.E167K in PNPLA3 and TM6SF2 genes, respectively, associate with development of hepatic fibrosis and cirrhosis in a geographically novel cohort of Pakistani chronic hepatitis C (CHC) patients.
METHODS: In total, 502 Pakistani CHC patients [242 males, median age 40 years, 220 with significant hepatic fibrosis, including 114 with cirrhosis] were genotyped for PNPLA3 and TM6SF2 variants using TaqMan genotyping assays. Associations between genotypes, biochemical and clinical parameters were evaluated.
RESULTS: Genotypic distributions for PNPLA3 and TM6SF2 polymorphisms conformed to Hardy-Weinberg equilibrium and did not associate with fibrosis grades ≥ F2 or cirrhosis in any of the genetic models tested (all p =  > 0.05). PNPLA3 and TM6SF2 variants did not modulate baseline characteristics and serum markers of liver injury in CHC patients. Similarly, increasing number of risk alleles of PNPLA3 and TM6SF2 polymorphisms had no trend effect on serum liver enzyme activities or proportion of CHC patients with significant or advanced fibrosis or cirrhosis (p =  > 0.05). The same trend of no association with hepatic fibrosis or cirrhosis persisted in the multivariate logistic regression models adjusting for age, gender, body mass index and HCV viral load (p =  > 0.05).
CONCLUSIONS: PNPLA3 and TM6SF2 variants do not appear to modulate development of hepatic fibrosis or cirrhosis in present CHC patients of Pakistani origin, and may be of more relevance in liver pathology involving abnormalities in hepatic fat accumulation. These results also reflect the divergent associations observed for different genetic modifiers of hepatic fibrosis and cirrhosis in distinct ethnicities.

The relationship of single nucleotide polymorphisms (SNPs) in patatin-like phospholipase domain containing 3 (PNPLA3) rs738409, transmembrane 6 superfamily member 2 (TM6SF2) rs58542926, and membrane bound O-acyltransferase domain containing 7 (MBOAT7) rs641738 with outcomes in patients with hepatitis C infection (HCV) is unclear. This study aimed to evaluate the association of PNPLA3, TM6SF2, and MBOAT7 with the baseline fibrosis stage and progression of liver fibrosis after HCV eradication with direct antiviral agents (DAAs). A total of 171 patients who received the DAAs at the Peking University First Hospital between June 2015 and June 2020 were included in the retrospective cohort. Transient elastography was used to determine liver stiffness measurements (LSMs) at the baseline, the end of treatment (EOT), 24 weeks after treatment (W24), and the last follow-up (LFU) visit. We used the QIAamp Blood Mini Kit (Qiagen) for whole blood genomic DNA extraction and polymerase chain reaction for PNPLA3, TM6SF2, and MBOAT7 amplification of the target gene. The PNPLA3 rs738409 SNP was associated with the baseline fibrosis stage in multivariate logistic regression analysis adjusted for other factors, and the adjusted odds ratio (OR) for advanced fibrosis (≥F3) at baseline was 2.52 (95% confidence interval[CI] = 1.096-5.794, p = 0.03). The G and GG alleles were predictive of advanced fibrosis (OR = 1.98, 95% CI = 1.021-4.196, p = 0.015; OR = 3.12, 95% CI = 1.572-6.536, p = 0.005). Similarly, the OR of TM6SF2 rs58542926 at baseline was 2.608 (95% CI = 1.081-6.29, p = 0.033). T and TT alleles were predictive of advanced fibrosis (OR = 2.3, 95% CI = 1.005-5.98, p = 0.007; OR = 3.05, 95% CI = 1.32-6.87, p = 0.001). After adjustment, the MBOAT7 rs641738 T plus TT alleles were not independently associated with the baseline fibrosis stage (95% CI = 0.707-2.959, p = 0.312). At the EOT, there were 35 patients and 136 patients in the fibrosis improvement and fibrosis non-improvement group, respectively. Logistic regression analysis showed that the G allele in PNPLA3 rs738409 was associated with fibrosis progression (OR = 2.47, 95% CI = 1.125-5.89, p = 0.003). The GG alleles were predictive of fibrosis progression (OR = 2.95, 95% CI = 1.35-6.35, p = 0.005). Similarly, the ORs of the T and TT alleles in TM6SF2 rs58542926 for fibrosis progression were 1.82 and 2.21, respectively (95% CI = 1.006-5.373, p = 0.045; 95% CI = 1.18-5.75, p = 0.01). At the W24 visit, we found that there was an association between the G allele in PNPLA3 rs738409 and fibrosis progression (OR = 2.218, 95% CI = 1.095-5.631, p = 0.015). Moreover, GG alleles were also predictive for fibrosis progression (OR = 2.558, 95% CI = 1.252-5.15, p = 0.008). Similarly, the OR of T allele and TT alleles in TM6SF2 rs58542926 for fibrosis progression was 2.056 and 2.652 (95% CI = 1.013-5.592, p = 0.038; 95% CI = 1.25-5.956, p = 0.015). For additional affirmation, we surveyed fibrosis progression utilizing the Cox proportional hazards model. G and GG alleles in PNPLA3 rs738409 were associated with an increased risk of progression to advanced fibrosis in multivariate model (hazard ratio [HR]1.566, 95% CI = 1.02-2.575, p = 0.017; and HR2.109, 95% CI = 1.36-3.271, p = 0.001, respectively). Besides, T and TT alleles in TM6SF2 rs58542926 were associated with an increased risk of progression to advanced fibrosis in multivariate model (HR = 1.322, 95% CI = 1.003-1.857, p = 0.045; and HR = 1.855, 95% CI = 1.35-2.765, p = 0.006, respectively). In contrast, rs641738 in MBOAT7 did not show a significant trend in the univariate and multivariate models. The PNPLA3 CG/GG SNP at rs738409 and TM6SF2 CT/TT SNP at rs58542926 were associated with the baseline fibrosis stage and fibrosis progression after HCV eradication with DAAs.

Genetic factors associated with non-alcoholic fatty liver disease (NAFLD) remain incompletely understood. To date, most genome-wide association studies (GWASs) have adopted radiologically assessed hepatic triglyceride content as the reference phenotype and so cannot address steatohepatitis or fibrosis. We describe a GWAS encompassing the full spectrum of histologically characterised NAFLD.
The GWAS involved 1,483 European NAFLD cases and 17,781 genetically matched controls. A replication cohort of 559 NAFLD cases and 945 controls was genotyped to confirm signals showing genome-wide or close to genome-wide significance.
Case-control analysis identified signals showing p values ≤5 × 10-8 at 4 locations (chromosome [chr] 2 GCKR/C2ORF16; chr4 HSD17B13; chr19 TM6SF2; chr22 PNPLA3) together with 2 other signals with p <1 × 10-7 (chr1 near LEPR and chr8 near IDO2/TC1). Case-only analysis of quantitative traits showed that the PNPLA3 signal (rs738409) had genome-wide significance for steatosis, fibrosis and NAFLD activity score and a new signal (PYGO1 rs62021874) had close to genome-wide significance for steatosis (p = 8.2 × 10-8). Subgroup case-control analysis for NASH confirmed the PNPLA3 signal. The chr1 LEPR single nucleotide polymorphism also showed genome-wide significance for this phenotype. Considering the subgroup with advanced fibrosis (≥F3), the signals on chr2, chr19 and chr22 maintained their genome-wide significance. Except for GCKR/C2ORF16, the genome-wide significance signals were replicated.
This study confirms PNPLA3 as a risk factor for the full histological spectrum of NAFLD at genome-wide significance levels, with important contributions from TM6SF2 and HSD17B13. PYGO1 is a novel steatosis modifier, suggesting that Wnt signalling pathways may be relevant in NAFLD pathogenesis.
Non-alcoholic fatty liver disease is a common disease where excessive fat accumulates in the liver and may result in cirrhosis. To understand who is at risk of developing this disease and suffering liver damage, we undertook a genetic study to compare the genetic profiles of people suffering from fatty liver disease with genetic profiles seen in the general population. We found that particular sequences in 4 different areas of the human genome were seen at different frequencies in the fatty liver disease cases. These sequences may help predict an individual\'s risk of developing advanced disease. Some genes where these sequences are located may also be good targets for future drug treatments.

Metabolic syndrome (MetS) and genetic polymorphisms PNPLA3 rs738409, TM6SF2 rs58542926 and MBOAT7 rs641738 are known inductors of non-alcoholic fatty liver disease (NAFLD). However, knowledge about how these affect the mortality of subjects with NAFLD is scarce. Therefore, we investigated the impact of MetS, PNPLA3 rs738409, TM6SF2 rs58542926 and MBOAT7 rs641738 on overall and cardiovascular disease (CVD) specific mortality among subjects with or without NAFLD. NAFLD diagnosis was based on liver ultrasound at the baseline. After this and other comprehensive examinations, 958 middle-aged Finns, 249 with NAFLD, were followed for 21 years. The mortality data was gathered from the National Death Registry. After multiple adjustments, the NAFLD individuals with MetS had increased risk of overall mortality as compared to the NAFLD subjects without MetS [2.054 (1.011-4.173, p = .046)]. However, PNPLA3 rs738409 [1.049 (0.650-1.692, p = .844)], TM6SF2 rs58542926 [0.721 (0.369-1.411, p = .340)] or MBOAT7 rs641738 [0.885 (0.543-1.439, p = .621)] did not affect the overall mortality. MetS was also a marker of increased risk of CVD mortality (15% vs. 2%, p = .013) while genetic polymorphisms did not affect CVD mortality. In conclusion, MetS, but not the gene polymorphisms studied, predicts increased overall and CVD-specific mortality among NAFLD subjects.

Liver steatosis is one of the side effects of chemotherapy. The PNPLA3 p.I148M, TM6SF2 p.E167K and MBOAT7 p.G17E variants represent genetic determinants for progressive liver diseases. Here, we investigate their association with chemotherapy-associated steatosis.
Prospectively, we recruited 87 patients undergoing systemic chemotherapy for gastrointestinal cancers. Hepatic fat (controlled attenuation parameter, CAP) and liver stiffness (LSM) were measured non-invasively before the initiation of chemotherapy (T0) and after at least two (T1) and four cycles (T2). Genetic variants were genotyped using allelic discrimination assays.
In the final dataset (n = 60) patients demonstrated the following CAP values: T0 - 215.0 ± 55.7 dB/m, T1 - 223.3 ± 53.6 dB/m, T2 - 223.4 ± 56.7 dB/m, consistent with mild steatosis. Initial CAP correlated with BMI (P < 0.01) and serum triglyceride concentrations (P = 0.03). Whereas at T0 none of the variants was associated with CAP or LSM, carriers of the prosteatotic PNPLA3 p.148M allele showed significantly (P = 0.008) higher steatosis at T1 as compared to patients carrying the homozygous wild-type genotype [II].
Our preliminary results show that patients carrying the PNPLA3 p.I148 M risk allele might be prone to hepatic fat accumulation during chemotherapy. Further studies are be needed to validate the clinical value of these findings.