Patatin-like Phospholipase Domain-containing Protein 3 I148M Research Articles

The health care experience of adults with metabolic dysfunction-associated steatohepatitis and influence of PNPLA3: A qualitative study.

Metabolic dysfunction-associated steatohepatitis (MASH) is a progressive form of metabolic dysfunction-associated steatotic liver disease, for which there is limited information about patient experience, including the patient journey. In this study, we conducted interviews with patients with MASH to qualitatively evaluate the patient journey and help elucidate the experiences of this patient population. We also investigated if the patatin-like phospholipase domain-containing protein 3 (PNPLA3) I148M variant (non-Hispanic) or being of Hispanic ethnicity may influence patient experiences because these 2 subgroups develop advanced liver disease more frequently than other patient groups. One-to-one interviews were conducted with 28 adults (with PNPLA3 I148M genetic variant, n = 10; Hispanic, n = 8) living in the United States who had been diagnosed with MASH with liver fibrosis. Patients were asked open-ended questions about their experiences before, at, and after their diagnosis. The data collected found that patients experienced a long process of misdiagnoses before their diagnosis of MASH, a lack of clear information provided by clinicians, and limited accessibility to support groups. Hispanic patients reported "impact on family/friends" (75%) and "fear of disease progression" (75%) more frequently than the other patient cohorts interviewed. This is the first report of "fear of progression" in patients with MASH. No patients who were White and had the PNPLA3 I148M variant reported nausea/vomiting, in contrast to other patient cohorts. This qualitative study identified key aspects of the patient journey that are important for clinical providers and medical teams to recognize. We also propose a new algorithm that could be developed to help screen relatives of patients who are found to carry the PNPLA3 I148M variant.

Association of liver fibrosis with extrahepatic cancer in steatotic liver disease patients with PNPLA3 I148M GG genotype.

The impacts of patatin-like phospholipase domain-containing protein 3 (PNPLA3) I148M-rs738409, methylenetetrahydrofolate reductase (MTHFR) Ala222Val-rs1801133, and aldehyde dehydrogenase 2 (ALDH2) Glu504Lys-rs671 on the outcomes of Taiwanese patients with steatotic liver disease (SLD) have remained elusive. An 8-year prospective cohort study of patients with (n = 546) and without (n = 580) SLD (controls) was undertaken in a Taiwanese tertiary care center. The 546 SLD patients comprised 306 (56.0%) men and 240 (44.0%) women with mean ages of 53.3 and 56.4 years, respectively. Compared with the controls, SLD patients had an increased frequency of the PNPLA3 I148M-rs738409 GG genotype (25.5 vs. 5.9%, p = 0.001). Among the SLD patients, 236 (43.1%) suffered cardiovascular events, 52 (9.5%) showed extrahepatic cancers, 13 (2.38%) experienced hepatic events, including hepatocellular carcinoma (n = 3, 0.5%) and liver cirrhosis (n = 8, 1.47%), and none died. The Fibrosis-4 (FIB-4) scores were associated with extrahepatic cancer (hazard ratio [HR] 1.325; 95% confidence interval [CI], 1.038-1.691) and cirrhosis development (HR 1.532; 95% CI, 1.055-2.224), and the PNPLA3 I148M-rs738409 G allele (β = 0.158, 95% CI, 0.054-0.325) was associated with the FIB-4 score. Stratified analyses showed that the impact of the FIB-4 score on extrahepatic cancer development was evident only in SLD patients with the PNPLA3 I148M-rs738409 GG genotype (HR 1.543; 95% CI, 1.195-1.993) and not in patients with the GC or CC genotype. Moreover, the ALDH2 Glu504Lys-rs671 G allele had a dose-dependent effect on alcoholism, and the MTHFR and ALDH2 genotypes were not significantly associated with SLD patient outcomes. In conclusion, special vigilance should be exercised for emerging extrahepatic cancer in SLD patients with the PNPLA3 I148M-rs738409 GG genotype and high FIB-4 scores.

An association study of the PNPLA3 I148M polymorphism (rs738409) with serum lipids in patients with dyslipidemia

Aim: One single nucleotide polymorphism (SNP) rs738409 in the patatin-like phospholipase domain-containing protein 3 (PNPLA3) gene has been considered a major genetic risk factor of nonalcoholic fatty liver disease (NAFLD). Data have indicated that NAFLD is related to insulin resistance and dyslipidemia, but whether rs738409 is associated with circulating lipid and lipoproteins is not fully elucidated. The main aim of this study was to assess the association of rs738409 with lipid and lipoprotein levels in patients with dyslipidemia. Methods: This was a post-hoc analysis of a study in patients with dyslipidemia recruited on an outpatient basis. Morning blood samples were collected after a 12-h fast. Genomic DNA was extracted from whole-blood samples. Results: One hundred seventy-five patients with dyslipidemia were included (97 women). Lipid levels [total cholesterol (TC), triglycerides (TGs), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C)] or glycosylated hemoglobin (HbA1c) were not associated with the SNP, even after adjustment for gender, body mass index (BMI) and type 2 diabetes mellitus (T2DM), using either the additive (CC vs. CG vs. GG) or the dominant (CC vs. GG + CG) inheritance model. When data were stratified for obesity, significant associations between the variant and TC (P = 0.014) or LDL-C levels (P = 0.046) in the non-obese were observed. Pairwise comparison revealed significant changes only in TC between CC and CG genotypes (P = 0.012). Conclusions: No association was shown between rs738409 SNP and lipid/lipoprotein levels in patients with dyslipidemia. In subgroup analysis, TC was higher in non-obese, but not in obese, patients with CC, compared to CG carriers.

PNPLA3 I148M and response to treatment for hepatic steatosis: A systematic review.

It is unclear whether the patatin-like phospholipase domain-containing protein 3 (PNPLA3) rs738409 C-to-G single nucleotide polymorphism, resulting in the substitution of isoleucine to methionine at position 148 (I148M), impedes regression of hepatic steatosis when treating non-alcoholic fatty liver disease (NAFLD). Investigate if carriage of the PNPLA3 148M allele affects the anti-steatotic efficacy of all possible anti-NAFLD interventions, identify gaps in current knowledge and provide guidance for individual treatment. Research available in public databases was searched up to 13 November 2022. Studies were included if a treatment in NAFLD patients decreased hepatic steatosis in the pooled patient group or a PNPLA3 I148M polymorphism subgroup (II/IM/MM). The risk of bias was assessed using the Cochrane Risk-Of-Bias 2 Tool and the Newcastle-Ottawa Scale. Moderate evidence indicates that NAFLD patients homozygous for the PNPLA3 148M allele benefit less or not at all from omega-3 carboxylic acids to decrease liver fat, while the PNPLA3 148I allele shows moderate benefit. Low evidence suggests that interventions employing lifestyle changes are more effective to reduce liver fat in NAFLD patients homozygous for the PNPLA3 148M allele compared to patients with wild-type PNPLA3. NAFLD patients homozygous for the PNPLA3 148M allele might not benefit from omega-3 carboxylic acids to reduce hepatic steatosis in contrast to patients with wild-type PNPLA3. Instead, patients with two PNPLA3 148M alleles should be especially advised to adopt lifestyle changes. Genotyping for PNPLA3 I148M should be encouraged in therapeutic studies for NAFLD. CRD42022375028.

Synergistic Associations of PNPLA3 I148M Variant, Alcohol Intake, and Obesity With Risk of Cirrhosis, Hepatocellular Carcinoma, and Mortality

Alcohol drinking and obesity are associated with an increased risk of cirrhosis and hepatocellular carcinoma (HCC), but the risk is not uniform among people with these risk factors. Genetic variants, such as I148M in the patatin-like phospholipase domain-containing protein 3 (PNPLA3) gene, may play an important role in modulating cirrhosis and HCC risk. To investigate the joint associations of the PNPLA3 I148M variant, alcohol intake, and obesity with the risk of cirrhosis, HCC, and liver disease-related mortality. This prospective cohort study analyzed 414 209 participants enrolled in the UK Biobank study from March 2006 to December 2010. Participants had no previous diagnosis of cirrhosis and HCC and were followed up through March 2021. Self-reported alcohol intake (nonexcessive vs excessive), obesity (body mass index ≥30 [calculated as weight in kilograms divided by height in meters squared]), and PNPLA3 I148M variant status (noncarrier, heterozygous carrier, or homozygous carrier) from initial assessment. The primary outcomes were incident cirrhosis and HCC cases and liver disease-related death ascertained from inpatient hospitalization records and death registry. The risks were calculated by Cox proportional hazards regression models. A total of 414 209 participants (mean [SD] age, 56.3 [8.09] years; 218 567 women [52.8%]; 389 452 White race and ethnicity [94.0%]) were included. Of these participants, 2398 participants (0.6%) developed cirrhosis (5.07 [95% CI, 4.87-5.28] cases per 100 person-years), 323 (0.1%) developed HCC (0.68 [95% CI, 0.61-0.76] cases per 100 person-years), and 878 (0.2%) died from a liver disease-related cause (1.76 [95% CI, 1.64-1.88] cases per 100 person-years) during a median follow-up of 10.9 years. Synergistic interactions between the PNPLA3 I148M variant, obesity, and alcohol intake were associated with the risk of cirrhosis, HCC, and liver disease-related mortality. The risk of cirrhosis increased supramultiplicatively (adjusted hazard ratio [aHR], 17.52; 95% CI, 12.84-23.90) in individuals with obesity, with excessive drinking, and who were homozygous carriers compared with those with no obesity, with nonexcessive drinking, and who were noncarriers. Supramultiplicative associations between the 3 factors and risks of HCC were found in individuals with 3 risk factors (aHR, 30.13; 95% CI, 16.51-54.98) and liver disease-related mortality (aHR, 21.82; 95% CI, 13.78-34.56). The PNPLA3 I148M variant status significantly differentiated the risk of cirrhosis, HCC, and liver disease-related mortality in persons with excessive drinking and obesity. This study found synergistic associations of the PNPLA3 I148M variant, excessive alcohol intake, and obesity with increased risk of cirrhosis, HCC, and liver disease-related death in the general population. The PNPLA3 I148M variant status may help refine the risk stratification for liver disease in persons with excessive drinking and obesity who may need early preventive measures.

PNPLA3 I148M gene variant and chronic kidney disease in type 2 diabetic patients with NAFLD: Clinical and experimental findings.

Emerging evidence suggests an association between patatin-like phospholipase domain-containing protein-3 (PNPLA3) rs738409 (I148M protein variant) and risk of chronic kidney disease (CKD), but the mechanisms underpinning this association are poorly understood. We studied 157 patients with type 2 diabetes (T2DM) who underwent ultrasonography and vibration-controlled transient elastography for diagnosing nonalcoholic fatty liver disease (NAFLD). CKD was defined as estimated glomerular filtration rate (e-GFR) <60mL/min/1.73m2 and/or abnormal albuminuria. We surveyed PNPLA3 mRNA expression in human tissues, using the liver as a positive control, and also measured PNPLA3 mRNA and protein expression levels in human cell lines represented in the kidney and the liver. In all, 112 patients had NAFLD and 43 had CKD. Patients homozygous for the I148M variant (n=11) had lower e-GFR levels (60.6±11.7 vs 77.8±15.9 vs 83.5±16.5mL/min/1.73m2 , P=.0001) and higher prevalence of CKD (63.6% vs 24.2% vs 25.0%, P=.028), compared to those with I/M (n=66) and I/I (n=80) PNPLA3 genotype. The association of I148M homozygosity with lower e-GFR levels (P<.0001) and higher risk of CKD (adjusted-odds ratio 6.65; 95% CI 1.65-26.8, P=.008) was independent of liver disease severity (as detected by liver stiffness ≥7kPa) and other risk factors. PNPLA3 mRNA expression was greatest in liver and renal cortex, and podocytes showed high PNPLA3 mRNA and protein levels, comparable to that of hepatocytes and hepatic stellate cells respectively. The PNPLA3 I148M variant was associated with CKD, independently of common renal risk factors and severity of NAFLD PNPLA3 expression levels were particularly high in renal podocytes.

Patatin-Like Phospholipase Domain-Containing Protein 3 I148M and Liver Fat and Fibrosis Scores Predict Liver Disease Mortality in the U.S. Population.

Fatty liver causes premature death worldwide and requires long-term health care. We examined relationships of liver disease markers, including patatin-like phospholipase domain-containing protein 3 (PNPLA3) I148M, with mortality in the U.S. National Health and Nutrition Examination Survey, 1988-1994, with 27 years of linked mortality data. We studied 13,298 viral hepatitis negative adults who fasted at least 4 hours using the nonalcoholic fatty liver disease (NAFLD) liver fat score and NAFLD fibrosis score. PNPLA3 I148M was genotyped in a subgroup of participants from 1991 to 1994 (n=5,640). Participants were passively followed for mortality, identified by death certificate underlying or contributing causes, by linkage to the National Death Index through 2015. During follow-up (median, 23.2years), cumulative mortality was 33.2% overall and 1.1% with liver disease, including primary liver cancer. Increased liver disease mortality was associated with PNPLA3 I148M (hazard ratio [HR], 2.9; 95% confidence interval [CI], 0.9-9.8) and 148M genotypes (HR, 18.2; 95% CI, 3.5-93.8), an intermediate (HR, 3.8; 95% CI, 1.3-10.7) or high (HR, 12.6; 95% CI, 4.3-36.3) NAFLD liver fat score, and a high NAFLD fibrosis score (HR, 12.2; 95% CI, 1.9-80.6) adjusted for risk factors. Survival curves suggest that increased mortality risk with two 148M alleles was greatest beginning in the second decade of follow-up. Overall, but not cardiovascular disease, mortality was associated with the PNPLA3 148M allele, and both mortality outcomes were associated with higher fat and fibrosis scores. In the U.S. population, PNPLA3 I148M and higher NAFLD liver fat and fibrosis scores were associated with increased liver disease mortality. Genetic variant PNPLA3 I148M may complement other liver disease markers for NAFLD surveillance.

The effect of PNPLA3 polymorphism as gain in function mutation in the pathogenesis of non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is often associated withmetabolic syndrome (type 2 diabetes, hypertension, hypertriglyceridemia, insulin resistance, and obesity). NAFLD is multi-factorial in pathogenesis with some genetic predisposition. The variant patatin-like phospholipase domain-containing protein 3 (PNPLA3) is known to be an independent risk factor for hepatocellular cancer (HCC). The aim of this study was to investigate the role of PNPLA3 polymorphism as the risk factor for NAFLD. Patients had histological, ultrasonographic, biopsy evidence of NAFLD (n=248) and 81 controls were studied forPNPLA3 polymorphism. PNPLA3 genotyping was done from peripheral blood DNA by real-time polymerase chain reaction (RT-PCR). PNPLA3 genotyping of the groups NAFLD (CC [n = 76], CG [n = 83], GG [n = 89]) and control (CC [n= 42], CG [n = 22], GG [n = 17]) was determined. In the patient group, the G allele was 261 (52.63%) and the C allele was 235 (47.37%), whereas in the control group, the G allele was 56 (34.54%) and the C allele was 106 (65.43%). In our study, 53 out of 174 women had GG allele and 54 out of 155 men had GG allele. The findings suggest that there is a predominant relationship between men with PNPLA3 I148M variant with NAFLD in women. Patients with NAFLD carrying PNPLA3 rs738409 G>C variant are at higher risk of NAFLD.

PNPLA3 I148M Polymorphism in Patients with Nonalcoholic Fatty Liver Disease, Obesity and Prediabetes.

Nonalcoholic fatty liver disease (NAFLD) is closely associated with obesity and insulin resistance, and therefore predisposes to type 2 diabetes and cardiovascular diseases. Lipid deposition in the liver seems to be critical in the pathogenesis of NAFLD. A common genetic variant, the patatin-like phospholipase domain-containing protein 3 (PNPLA3) has been associated with NAFLD. The aim of the present study was to evaluate the association between PNPLA3, key gene of lipid metabolism and the metabolic traits in obesity NAFLD patients with and without prediabetes. A total of 208 obese NAFLD patients without (n=125) and with prediabetes (n=83) were included. The genotyping of PNPLA3 I148M variant (rs738409) was performed by restriction analysis. Regarding rs738409 (I148M) polymorphism, CG genotype was positively correlated with prediabetes, insulin resistance, dyslipidemia and metabolic syndrome compared to the wild CC genotype. The carriers of the PNPLA3 I148M variant have 9.6-fold higher risk of glucose disturbances compared to wild genotype (OR 9.649, 95%CI 2.100-44.328, р=0.004). The carriers of the PNPLA3 I148M variant also have a 3 times higher risk for the presence of metabolic syndrome (OR 2.939, 95% CI: 1.590-5.434, p=0.001) and a 2.1-fold higher risk for the presence of insulin resistance (OR 2.127, 95% CI: 1.078-4.194, p=0.029). PNPLA3 I148M is associated with increased risk of prediabetes, metabolic syndrome and insulin resistance in obese patients with NAFLD.

Interaction of TM6SF2 E167K and PNPLA3 I148M variants in NAFLD in northeast China

Introduction and aimThis study aimed to confirm the association of the transmembrane 6 superfamily member 2 (TM6SF2) E167K variant with non-alcoholic fatty liver disease (NAFLD) and the degree of steatosis, as well as the additive effect of body mass index (BMI) or the patatin-like phospholipase domain-containing protein 3 (PNPLA3) I148M and TM6SF2 E167K variants in NAFLD. Materials and methodsA total of 158 NAFLD patients and 158 matched controls were recruited. Steatosis was classified as mild, moderate and severe by FibroScan. Associations between the TM6SF2 E167K variant and NAFLD as well as clinical parameters were evaluated. ResultsAlthough the frequency of the T allele was low in the Chinese population (MAF=7.4%), there was still a significant association between the E167K variant and NAFLD (odds ratio=3.379, 95% confidence interval: 1.500–7.612, P=0.003). In particular, the TM6SF2 genotype was also associated with the degree of steatosis (P=0.023). The TM6SF2 variant was associated with increased alanine aminotransferase (ALT) but no other clinical parameters, such as aspartate aminotransferase (AST), alkaline phosphatase (ALP) and lipids. Notably, we also found that an additive effect of the TM6SF2 E167K and PNPLA3 I148M variants in NAFLD. Furthermore, we did not identify an association between the TM6SF2 E167K variant and NAFLD in the non-obese population. ConclusionThe TM6SF2 E167K variant was associated with NAFLD in northeast China, and there was an interaction between the PNPLA3 I148M and TMS6F2 E167K variants in NAFLD.

The Genetic Variant I148M in PNPLA3 Is Associated With Increased Hepatic Retinyl-Palmitate Storage in Humans.

Previous studies revealed that the common sequence variant I148M in patatin-like phospholipase domain-containing protein 3 (PNPLA3) is associated with liver fat content and liver diseases, but not with insulin resistance. Recent data suggest that the PNPLA3 I148M variant has reduced retinyl-palmitate lipase activity in hepatic stellate cells. We hypothesized that the PNPLA3 I148M variant is associated with elevated retinyl-palmitate storage in human liver as a potential link to the clinical pathology. Design/Setting and Participants: Using HPLC, we quantified the retinoid metabolites in liver tissue extracts obtained from 42 human subjects, including 13 heterozygous and six homozygous carriers of the minor PNPLA3 I148M variant. Retinyl-palmitate is elevated in human livers of homozygous PNPLA3 I148M allele carriers Results: The PNPLA3 I148M variant was associated with a significant increase (1.4-fold) in liver fat. The content of retinyl-palmitate was elevated and the ratio of retinol/retinyl-palmitate was reduced in liver extracts obtained from homozygous PNPLA3 I148M minor allele carriers. In a multivariate model including liver fat content, these differences remained significant independent of liver fat content. The content of the minor retinyl-fatty acid esters was similarly increased in homozygous PNPLA3 I148M carriers. The increased content of hepatic retinyl-palmitate and the reduced ratio of retinol/retinyl-palmitate in PNPLA3 I148M minor allele carriers support in vitro findings of an altered retinyl-palmitate lipase activity. Our results indicate that the PNPLA3 I148M variant is relevant for the retinyl-palmitate content in human liver, providing a possible link to chronic liver disease.

Treating liver fat and serum triglyceride levels in NAFLD, effects of PNPLA3 and TM6SF2 genotypes: Results from the WELCOME trial

Genetic variation in both patatin-like phospholipase domain-containing protein-3 (PNPLA3) (I148M) and the transmembrane 6 superfamily member 2 protein (TM6SF2) (E167K) influences severity of liver disease, and serum triglyceride concentrations in non-alcoholic fatty liver disease (NAFLD), but whether either genotype influences the responses to treatments is uncertain. One hundred three patients with NAFLD were randomised to omega-3 fatty acids (DHA+EPA) or placebo for 15-18months in a double blind placebo controlled trial. Erythrocyte enrichment with DHA and EPA was measured by gas chromatography. PNPLA3 and TM6SF2 genotypes were measured by PCR technologies. Multivariable linear regression and analysis of covariance were undertaken to test the effect of genotypes on omega-3 fatty acid enrichment, end of study liver fat percentage and serum triglyceride concentrations. All models were adjusted for baseline measurements of each respective outcome. Fifty-five men and 40 women (Genotypes PNPLA3 I148M, 148I/I=41, 148I/M=43, 148M/M=11; TM6SF2 E167K 167E/E=78, 167E/K+167K/K=17 participants) (mean ± SD age, 51 ± 11 years) completed the trial. Adjusting for baseline measurement, measured covariates and confounders, PNPLA3 148M/M variant was independently associated with percentage of DHA enrichment (B coefficient -1.02 (95% CI -1.97, -0.07), p=0.036) but not percentage of EPA enrichment (B coefficient -0.31 (95% CI -1.38, 0.75), p=0.56). This genotype was also independently associated with end of study liver fat percentage (B coefficient 9.5 (95% CI 2.53, 16.39), p=0.008), but not end of study triglyceride concentration (B coefficient -0.11 (95% CI -0.64, 0.42), p=0.68). PNPLA3 148M/M variant influences the changes in liver fat and DHA tissue enrichment during the trial but not the change in serum triglyceride concentration.

Patatin-like phospholipase domain containing-3 gene (PNPLA3) I148M polymorphism and liver damage in chronic hepatitis C Egyptian patients

Hepatitis C virus (HCV) has been associated with high prevalence of steatosis and fibrosis. The impact of single-nucleotide polymorphisms (SNP) of patatin-like phospholipase domain-containing protein 3 (PNPLA3) on the development of steatosis and fibrosis is not clarified for Egyptian patients with chronic hepatitis C (CHC).The aim of the study was to assess whether the PNPLA3 I148M variant predisposes to steatosis, and to progressive liver damage, as evaluated fibrosis stage in Egyptian patients with CHC. Subjects and methods218 CHC Egyptian patients were enrolled in the study, they were grouped by Ishak stage of fibrosis on liver biopsy into group I (fibrosis score 0 or 1; n 81), group II (fibrosis score 2 or 3; n 72) and group III (fibrosis score 4–6; n 65). DNA was amplified by polymerase chain reaction. ResultsPNPLA3 genotype was not associated with metabolic parameters, including body mass index (BMI) and lipid levels, but the presence of G allele is associated with higher liver enzymes and viral loads levels. The PNPLA3 G allele was associated with the severity (stage) of fibrosis (X2=35.83, P=0.000). Steatosis was detected in 40.7% of C allele carriers and 58.53% of G allele carriers. The rs738409 G allele was significantly associated with steatosis in the overall CHC patients with different fibrotic stages (X2=6.023, P=0.018) odds ratio (OR) and 95% CI=1.99 (1.146–3.47). ConclusionSteatosis and fibrosis severity seems to be PNPLA3 I148M regulated, independently to metabolic parameters but with significant association with viral loads and liver enzymes values in Egyptian patients with CHC.

PNPLA3 in end-stage liver disease: alcohol consumption, hepatocellular carcinoma development, and transplantation-free survival.

The rs738409 variant (I148M) of the patatin-like phospholipase domain-containing protein 3 (PNPLA3) gene is associated with several liver malfunctions. Its impact on end-stage liver disease has not been addressed yet. The I148M polymorphism was genotyped in a well-characterized cohort of 421 Caucasian patients and retrospectively analyzed from the time of enrollment at Eurotransplant. The G allele of the I148M variant was significantly overrepresented in patients with alcoholic liver disease (ALD, P < 0.001) and associated with hepatocellular carcinoma (HCC) development (odds ratio [OR] = 2.399; 95% confidence interval [CI]: 1.292-4.455; P = 0.008) while not affecting the other liver disease entities. Time until hydropic decompensation (P = 0.04) and hepatic encephalopathy (P = 0.043) was significantly impaired for ALD patients carrying either one or two mutated G alleles. Actuarial survival free of liver transplantation was further reduced for ALD carriers of the I148M variant (CC = 30.7 months ± 7.9, 95% CI: 15.1-46.2 vs CG/GG: 17.1 months ± 3.3, 95% CI: 3.3-10.6; P = 0.012) compared with wild-type patients. Cox multivariate analysis identified the PNPLA3 I148M genotype as an independent predictor actuarial survival free of liver transplantation (OR = 1.77; 95% CI: 1.27-2.47; P = 0.001). In end-stage liver disease patients, we identified ALD to be predominantly affected by the PNPLA3 I148M variant resulting in an increased risk of HCC and reduced transplantation free survival. Genetic testing of the I148M genotype in ALD patients awaiting liver transplantation might be beneficial for these patients.

Non-alcoholic fatty liver disease, metabolic syndrome and patatin-like phospholipase domain-containing protein3 gene variants

Background & aimsNon-alcoholic fatty liver disease was traditionally interpreted as a condition which may progress to liver-related complications. However, the increased mortality is primarily a result of cardiovascular diseases. It has been suggested that fatty liver can be considered as the hepatic consequence of the metabolic syndrome. The aim was to describe the different clinical presentations of non-alcoholic fatty liver disease on the basis of the patatin-like phospholipase domain-containing protein3 (PNPLA3) rs738409 gene variant. MethodsFatty liver was defined by ultrasonographic Hamaguchi's criteria in 211 consecutive subjects with non-alcoholic fatty liver disease. The rs738409 polymorphism was determined by TaqMan assays. Metabolic syndrome was defined according to ATPIII modified criteria. ResultsPrevalence of PNPLA3-148II, PNPLA3-148IM, and PNPLA3-148MM genotypes was 45.0%, 40.7%, and 14.3% respectively. Prevalence of metabolic syndrome progressively increased with the severity of liver steatosis (from 52.5% to 65.2%, and 82.3% respectively, p<0.01). The PNPLA3-148MM group had significantly lower mean serum triglycerides (p<0.001), Framingham cardiovascular risk score (p<0.01) and lower prevalence of metabolic syndrome (p<0.05) and its components. Age and HOMA-IR were positive independent predictors of metabolic syndrome, while a negative independent association was found between metabolic syndrome and the homozygotes PNPLA3 I148M variant. ConclusionsWe suggest a lower prevalence of MetS and reduced cardiovascular risk in NAFLD patients with PNPLA3MM genotype.

PNPLA3 I148M (rs738409) genetic variant and age at onset of at‐risk alcohol consumption are independent risk factors for alcoholic cirrhosis

Background & AimsEnvironmental and genetic factors contribute to alcoholic cirrhosis onset. In particular, age at exposure to liver stressors has been shown to be important in progression to fibrosis in hepatitis C individuals. However, no definite data on the role of age at onset of at-risk alcohol consumption are available. Moreover, patatin-like phospholipase domain-containing protein 3 (PNPLA3) I148M (rs738409) variant has been associated with alcoholic cirrhosis, but only in cross-sectional studies. The aim of this study was to investigate the role of age at onset of at-risk alcohol consumption and PNPLA3 I148M variant on alcoholic cirrhosis incidence.MethodsA total of 384 at-risk alcohol drinkers were retrospectively examined. The association among age at onset of at-risk alcohol consumption, PNPLA3 I148M variant and cirrhosis incidence was tested.ResultsA higher incidence of alcoholic cirrhosis was observed in individuals with an older (≥24 years) compared with a younger (<24) age at onset of at-risk alcohol consumption (P-value < 0.001). Moreover, PNPLA3 148M allele carriers showed an increased incidence of cirrhosis (P-value < 0.001). Both age at onset of at-risk alcohol consumption and PNPLA3 148M allele were independent risk factors for developing cirrhosis (H.R. (95% C.I.): 2.76 (2.18–3.50), P-value < 0.001; 1.53(1.07–2.19), P-value = 0.021 respectively). The 148M allele was associated with a two-fold increased risk of cirrhosis in individuals with a younger compared with an older age at onset of at-risk alcohol consumption (H.R. (95% C.I.): 3.03(1.53–6.00) vs. 1.61(1.09–2.38).ConclusionsAge at onset of at-risk alcohol consumption and PNPLA3 I148M genetic variant are independently associated with alcoholic cirrhosis incidence.

Genetic variant I148M in PNPLA3 is associated with the ultrasonography-determined steatosis degree in a Chinese population

BackgroundNonalcoholic fatty liver disease (NAFLD) is an escalating medical problem worldwide. A nonsynonymous single nucleotide polymorphism rs738409 (I148M) in patatin-like phospholipase domain-containing protein 3 (PNPLA3) predisposes susceptibility to NAFLD; however, its association with steatosis grade is inconsistent in the literature. In particular, there was no significant association found between I148M and steatosis grade in two East Asian-based studies. In this study we aim to investigate whether I148M is associated with the ultrasonography-determined steatosis degree in Chinese adults.Methods203 NAFLD cases and 202 matched controls were recruited. Cases were classified into mild, moderate and severe fatty liver by ultrasonography. Association between I148M and the ultrasonography-determined steatosis degree as well as other clinical parameters was evaluated.ResultsThe I148M variant was associated with the ultrasonography-determined steatosis degree with the M allele frequencies being 0.32, 0.54, and 0.87 in mild (n=105), moderate (n=83), and severe (n=15) cases, respectively (P–value = 7.6×10-8). We also confirmed the interaction between I148M variation and body mass index towards elevated plasma alanine aminotransferase levels in cases (P–value = 4.4×10-4).ConclusionThe PNPLA3 I148M variant is associated with the ultrasonography-determined steatosis degree in Chinese population.

APOC3 and PNPLA3 in non‐alcoholic fatty liver disease: Need to clear the air

See article in J. Gastroenterol. Hepatol. 2012; 27: 951–956.