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

PNPLA3 rs738409 Genetic Variant Inversely Correlates with Platelet Count, Thereby Affecting the Performance of Noninvasive Scores of Hepatic Fibrosis.

Noninvasive tests (NITs) including platelets (PLTs) have been proposed to replace hepatic biopsy for the diagnosis of nonalcoholic fatty liver disease (NAFLD), or as more recently redefined, metabolic dysfunction-associated steatotic liver disease (MASLD). There has been reported an inverse correlation between PLTs and progressive MASLD, which is also affected by the patatin-like phospholipase domain-containing protein 3 (PNPLA3) rs738409 C>G mutation. However, the correlation between low PLTs and PNPLA3 genotype has been poorly investigated. We stratified 1155 biopsy-proven MASLD patients according to PNPLA3 genotype. The hepatic expression of genes involved in megakaryopoiesis was investigated in n = 167 bariatric patients by RNAseq. PLT count progressively decreased according to the number of PNPLA3 at-risk alleles, irrespective of the presence of advanced fibrosis. The hepatic expression of genes involved in PLT biogenesis was associated with the PNPLA3 GG genotype. Finally, the presence of the PNPLA3 homozygosity flattened the accuracy of fibrosis-4 (FIB-4) in discriminating histological fibrosis stages. The PNPLA3 GG genotype may underpower the accuracy of NITs which include PLT count in identifying those patients with potentially reversible stages of fibrosis.

Correlations between PNPLA3 Gene Polymorphisms and NAFLD in Type 2 Diabetic Patients.

Background and Objectives: Non-alcoholic fatty liver disease is a worldwide significant public health problem, particularly in patients with type 2 diabetes mellitus. Identifying possible risk factors for the disease is mandatory for a better understandingand management of this condition. Patatin-like phospholipase domain-containing protein 3 (PNPLA3) has been linked to the development and evolution of fatty liver but not to insulin resistance. The aim of this study isto evaluate the relationships between PNPLA3 and fatty liver, metabolic syndrome and subclinical atherosclerosis. Materials and Methods: The study group consisted of patients with type 2 diabetes mellitus without insulin treatment. The degree of liver fat loading was assessed by ultrasonography, and subclinical atherosclerosis was assessed using carotid intima-media thickness (CIMT). PNPLA3 rs738409 genotype determination was performed by high-resolution melting analysis that allowed three standard genotypes: CC, CG, and GG. Results: Among the 92 patients, more than 90% showed various degrees of hepatic steatosis, almost 62% presented values over the normal limit for the CIMT. The majority of the included subjects met the criteria for metabolic syndrome. Genotyping of PNPLA3 in 68 patients showed that the difference between subjects without steatosis and subjects with hepatic steatosis was due to the higher frequency of genotype GG. The CC genotype was the most common in the group we studied and was significantly more frequent in the group of subjects with severe steatosis; the GG genotype was significantly more frequent in subjects with moderate steatosis; the frequency of the CG genotype was not significantly different among the groups.When we divided the group of subjects into two groups: those with no or mild steatosis and those with moderate or severe steatosis it was shown that the frequency of the GG genotype was significantly higher in the group of subjects with moderate or severe steatosis. PNPLA3 genotypes were not associated with metabolic syndrome, subclinical atherosclerosis, or insulin resistance. Conclusions: Our results suggest that PNPLA3 does not independently influence cardiovascular risk in patients with type 2 diabetes mellitus. The hypothesis that PNPLA3 may have a cardioprotective effect requires future confirmation.

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.

Effect of PNPLA3 polymorphism on diagnostic performance of various noninvasive markers for diagnosing and staging nonalcoholic fatty liver disease.

Patatin-like phospholipase domain-containing protein 3 (PNPLA3) I148M (rs738409) genotype influences clinical/biochemical characteristics in patients with nonalcoholic fatty liver disease (NAFLD), but whether PNPLA3-I148M (rs738409) genotype also influences the diagnostic performance of noninvasive diagnostic tests for NAFLD is uncertain. Our aim was to investigate the differences in diagnostic performance of noninvasive diagnostic tests for NAFLD according to PNPLA3-I148M (rs738409) genotype. Fifty-eight healthy controls and 349 patients with biopsy-proven NAFLD were included. Areas under the receiver operating characteristic curve (AUROCs) were calculated to predict hepatic steatosis (fatty liver index and hepatic steatosis index), nonalcoholic steatohepatitis (cytokeratin-18 M30 and M65), and significant fibrosis (≥F2 fibrosis) (fibrosis-4 and BARD), stratifying by rs738409 genotypes (CC and CG+GG groups). Fatty liver index and hepatic steatosis index showed good diagnostic performance for diagnosing steatosis only in the CG+GG group with AUROCs ranging from 0.819 to 0.832. Cytokeratin-18 M30 (AUROC = 0.688) and M65 (AUROC = 0.678) had suboptimal performance for diagnosing nonalcoholic steatohepatitis in the CG+GG group, whereas both had good performance (AUROC = 0.814 and 0.813, respectively) in the CC group. BARD score showed good performance in the CG+GG group compared with the CC group (AUROC = 0.805 and 0.532, respectively). Fibrosis-4 had suboptimal performance in the CG+GG group and good performance in the CC group (AUROC=0.662 and 0.801, respectively). Diagnostic performance of noninvasive tests for NAFLD varied markedly according to PNPLA3 genotypes. Clinicians should be aware that PNPLA3 genotype limits the clinical utility of noninvasive diagnostic tests for diagnosing NAFLD.

PNPLA3 rs738409 is associated with renal glomerular and tubular injury in NAFLD patients with persistently normal ALT levels.

Patatin-like phospholipase domain-containing protein 3 (PNPLA3) rs738409 polymorphism is associated with NAFLD severity and the PNPLA3 gene is expressed in the kidneys, but whether PNPLA3 rs738409 polymorphism is also associated with renal tubular injury (RTI) is uncertain. We assessed the effect of PNPLA3 genotypes on biomarkers of RTI and glomerular function in subjects with NAFLD who had either normal (nALT) or abnormal (abnALT) alanine aminotransaminase levels. Two hundred and seventeen patients with histologically proven NAFLD of which 75 had persistently nALT (below upper limit of normal for 3months) were included. Multivariable regression analyses were undertaken to test associations between PNPLA3 genotype and biomarkers of kidney dysfunction. The nALT patient group had higher urinary neutrophil gelatinase-associated lipocalin levels (u-NGAL, a biomarker of RTI) (P<.001), higher albuminuria (P=.039) and greater prevalence of chronic kidney disease (CKD; P=.046) than the abnALT group. The association between PNPLA3 GG genotype and risk of CKD and abnormal albuminuria remained significant after adjustment for kidney risk factors and severity of NAFLD histology, mostly in the nALT group. Similarly, PNPLA3 GG genotype was associated with higher u-NGAL levels in the nALT group, even after adjustment for the aforementioned risk factors and glomerular filtration-based markers (β-coefficient: 22.29, 95% CI: 0.99-43.60, P=.041). Patients with NAFLD and persistently nALT, who carry the PNPLA3 rs738409 G allele, are at higher risk of early glomerular and tubular damage. We suggest PNPLA3 genotyping may help identify patients with NAFLD at higher risk of RTI.

Human PNPLA3-I148M variant increases hepatic retention of polyunsaturated fatty acids.

The common patatin-like phospholipase domain-containing protein 3 (PNPLA3) variant I148M predisposes to nonalcoholic liver disease but not its metabolic sequelae. We compared the handling of labeled polyunsaturated fatty acids (PUFAs) and saturated fatty acids (SFA) in vivo in humans and in cells harboring different PNPLA3 genotypes. In 148M homozygous individuals, triglycerides (TGs) in very low-density lipoproteins (VLDL) were depleted of PUFAs both under fasting and postprandial conditions compared with 148I homozygotes, and the PUFA/SFA ratio in VLDL-TGs was lower relative to the chylomicron precursor pool. In human PNPLA3-148M and PNPLA3-KO cells, PUFA but not SFA incorporation into TGs was increased at the expense of phosphatidylcholines, and under lipolytic conditions, PUFA-containing diacylglycerols (DAGs) accumulated compared with PNPLA3-148I cells. Polyunsaturated TGs were increased, while phosphatidylcholines (PCs) were decreased in the human liver in 148M homozygous individuals as compared with 148I homozygotes. We conclude that human PNPLA3-I148M is a loss-of-function allele that remodels liver TGs in a polyunsaturated direction by impairing hydrolysis/transacylation of PUFAs from DAGs to feed phosphatidylcholine synthesis.

PNPLA3 I148M Variant Impairs Liver X Receptor Signaling and Cholesterol Homeostasis in Human Hepatic Stellate Cells.

The patatin‐like phospholipase domain‐containing protein 3 (PNPLA3) I148M variant predisposes to hepatic steatosis and progression to advanced liver injury with development of fibrosis, cirrhosis, and cancer. Hepatic stellate cells (HSCs) drive the wound healing response to chronic injury, and lack of liver X receptor (LXR) signaling exacerbates liver fibrogenesis by impairing HSC cholesterol homeostasis. However, the contribution of the I148M variant to this process is still unknown. We analyzed LXR expression and transcriptional activity in primary human HSCs and overexpressing LX‐2 cells according to PNPLA3 genotype (wild type [WT] versus I148M). Here we demonstrate that LXRα protein increased whereas LXR target gene expression decreased during in vitro activation of primary human HSCs. Notably, LXRα levels and signaling were reduced in primary I148M HSCs compared to WT, as displayed by decreased expression of LXR target genes. Moreover, reduced expression of cholesterol efflux and enzymes generating oxysterols was associated with higher total and free cholesterol accumulation whereas endogenous cholesterol synthesis and uptake were diminished in I148M HSCs. Luciferase assays on LXR response element confirmed decreased LXR transcriptional activity in I148M HSCs; in contrast the synthetic LXR agonist T0901317 replenished LXR functionality, supported by adenosine triphosphate‐binding cassette subfamily A member 1 (ABCA1) induction, and reduced collagen1α1 and chemokine (C‐C motif) ligand 5 expression. Conversely, the peroxisome proliferator‐activated receptor gamma (PPARγ) agonist rosiglitazone had only partial effects on the LXR target gene ABCA1, and neither diminished expression of proinflammatory cytokines nor increased de novo lipogenic genes in I148M HSCs. Conclusion: As a consequence of reduced PPARγ activity, HSCs carrying I148M PNPLA3 show impaired LXR signaling, leading to cholesterol accumulation. The use of a specific LXR agonist shows beneficial effects for diminishing sustained HSC activation and development of liver fibrogenesis.

Low Birthweight Increases the Likelihood of Severe Steatosis in Pediatric Non-Alcoholic Fatty Liver Disease.

Small for gestational age (SGA) is associated with an increased risk of non-alcoholic fatty liver disease (NAFLD). Our aim was to investigate the correlation of birthweight with the severity of liver damage in a large cohort of children with NAFLD. Two hundred and eighty-eight consecutive Caucasian Italian overweight/obese children with biopsy-proven NAFLD were included in the study. We examined the relative association of each histological feature of NAFLD with metabolic alterations, insulin-resistance, I148M polymorphism in the patatin-like phospholipase domain-containing protein 3 (PNPLA3) gene, and birthweight relative to gestational age. In the whole NAFLD cohort, 12.2% of patients were SGA, 62.8% appropriate for gestational age (AGA), and 25% large for gestational age (LGA). SGA children had a higher prevalence of severe steatosis (69%) and severe portal inflammation (14%) compared with the AGA and LGA groups. Notably, severe steatosis (>66%) was decreasing from SGA to AGA and LGA, whereas the prevalence of moderate steatosis (33-66%) was similar in three groups. The prevalence of type 1 NAFLD is higher in the LGA group with respect to the other two groups (25% vs.5.2% vs.9.4%), whereas the SGA group shows a higher prevalence of overlap type (85.8%) with respect to the LGA group (51.4%) but not compared with the AGA group (75%). At multivariable regression analysis, SGA at birth increased fourfold the likelihood of severe steatosis (odds ratio (OR) 4.0, 95% confidence interval (CI) 1.43-10.9, P=0.008) and threefold the likelihood of NAFLD Activity Score (NAS)≥5 (OR 2.98, 95% CI 1.06-8.33, P=0.037) independently of homeostasis model assessment of insulin resistance and PNPLA3 genotype. The PNPLA3-CC wild-type genotype was the strongest independent predictor of the absence of significant fibrosis (OR 0.26, 95% CI 0.13-0.52, P=<0.001). In children with NAFLD, the risk of severe steatosis is increased by SGA at birth, independent of and in addition to other powerful risk factors (insulin-resistance and I148M variant of the PNPLA3 gene).

Patatin-like phospholipase domain-containing protein 3 (PNPLA3): A potential role in the association between liver disease and bipolar disorder

ObjectiveDue to the increased prevalence of liver disease in patients with bipolar disorder, we examined the potential role of the patatin-like phospholipase domain-containing protein 3 (PNPLA3) variant among individuals with bipolar disorder and those with no mood disorder. MethodsWe used the National Health and Nutrition Examination Survey (NHANES) database (aged 15–39 years) to identify a group of individuals with a bipolar diagnosis and a control group of individuals with no mood disorder. A total of 1931 individuals were randomly selected, one from each family containing information on the PNPLA3 genotype to be used in the analysis. ResultsAnalyses revealed individuals with the recessive variant genotype (MM) had an adjusted odds ratio for bipolar disorder of about 4.6 compared to individuals with either IM or II genotypes of the PNPLA3 variant. Limitations and conclusionsLimitations of this study include the use of a lay-administered survey in for diagnosis of bipolar disorder in NHANES. The association between the PNPLA3 variant and bipolar disorder may help guide further work on medication effectiveness, treatment options, prevention approaches, and understanding potential medication side effects among specific subgroups of individuals with the MM genotype.

Bidirectional Relationships and Disconnects between NAFLD and Features of the Metabolic Syndrome.

Non-alcoholic fatty liver disease (NAFLD) represents a wide spectrum of liver disease from simple steatosis, to steatohepatitis, (both with and without liver fibrosis), cirrhosis and end-stage liver failure. NAFLD also increases the risk of hepatocellular carcinoma (HCC) and both HCC and end stage liver disease may markedly increase risk of liver-related mortality. NAFLD is increasing in prevalence and is presently the second most frequent indication for liver transplantation. As NAFLD is frequently associated with insulin resistance, central obesity, dyslipidaemia, hypertension and hyperglycaemia, NAFLD is often considered the hepatic manifestation of the metabolic syndrome. There is growing evidence that this relationship between NAFLD and metabolic syndrome is bidirectional, in that NAFLD can predispose to metabolic syndrome features, which can in turn exacerbate NAFLD or increase the risk of its development in those without a pre-existing diagnosis. Although the relationship between NAFLD and metabolic syndrome is frequently bidirectional, recently there has been much interest in genotype/phenotype relationships where there is a disconnect between the liver disease and metabolic syndrome features. Such potential examples of genotypes that are associated with a dissociation between liver disease and metabolic syndrome are patatin-like phospholipase domain-containing protein-3 (PNPLA3) (I148M) and transmembrane 6 superfamily member 2 protein (TM6SF2) (E167K) genotypes. This review will explore the bidirectional relationship between metabolic syndrome and NAFLD, and will also discuss recent insights from studies of PNPLA3 and TM6SF2 genotypes that may give insight into how and why metabolic syndrome features and liver disease are linked in NAFLD.

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.

PNPLA3 genotype increases susceptibility of nonalcoholic steatohepatitis among obese patients with nonalcoholic fatty liver disease

BackgroundThe patatin-like phospholipase domain-containing protein 3 (PNPLA3) rs738409 variant is associated with histologic disease severity in patients with nonalcoholic fatty liver disease (NAFLD); however, whether the PNPLA3 genotype has an effect on susceptibility of nonalcoholic steatohepatitis (NASH) from NAFLD among severely obese patients remains unclear. The objective of this study was to investigate the role of the PNPLA3 genotype on NASH in severely obese Asian patients with NAFLD. MethodsThe PNPLA3 rs738409 genotype was determined in 181 severely obese patients who underwent bariatric surgery. The diagnosis of NASH and the NAFLD activity score (NAS) were determined by liver histopathology. ResultsOf the 181 patients, 29 (16.0%), 60 (33.2%), and 92 (50.8%) were in the non-NAFLD, steatosis, and NASH groups, respectively. The PNPLA3 rs738409 GG genotype was associated with higher liver enzymes and a higher risk for NASH (odds ratio [OR], 3.72; 95% CI, 1.25–11.05). The GG genotype was also associated with histologic severity of NAFLD, including higher steatosis grade (OR, 9.94; 95% CI, 2.20–44.83 for patients with grade 3 steatosis) and NAS (OR, 11.49; 95% CI, 2.50–52.83 for patients with a NAS ≥5). Finally, multiple logistic regression also showed that the GG genotype was an independent risk factor for NASH (OR, 3.58; 95% CI, 1.15–11.12) in NAFLD patients. ConclusionThe PNPLA3 rs738409 GG genotype increases susceptibility of NASH in severely obese Asians with NAFLD and correlates to histologic severity of NAFLD.

Commentary: dissecting the PNPLA3 association with liver fat and stiffness, and interaction with diet

We read the article by Shen et al. with great interest, and highlighted some of the key features of this study.1 The authors conducted a prospective cohort study and reported that the rs738409 GG variant in patatin-like phospholipase domain-containing protein 3 (PNPLA3) genotype was associated with an increased risk of non-alcoholic fatty liver disease (NAFLD) by magnetic resonance spectroscopy (MRS) of the liver, and the presence of gene effect on trait was not explained by the diet history recorded by the food frequency questionnaire. In multivariable-adjusted analyses, metabolic syndrome was a much stronger correlate of presence of hepatic steatosis than PNPLA3 genotype. Incremental net reclassification rate (although not shown) by including PNPLA3 genotype in addition to clinical risk factors of NAFLD appeared modest, and not clinically significant, when these results are seen in context of the broader themes in the field at this time. This study provides validation that PNPLA3 genotype is associated with increased risk of NAFLD in an urban Asian population, predominantly of Chinese origin, residing in Hong Kong. The investigators also found that liver stiffness measured by transient elastography did not reveal any association with PNPLA3 genotype. These data suggest that liver stiffness in NAFLD is not affected by PNPLA3 genotype, and possibly other genetic variants may be associated with hepatic fibrosis and/or liver stiffness. Previous studies have shown that the association of the GG variant and hepatic lipid content is associated with the presence of other risk factors, such as severe obesity,2 visceral adiposity,3 increased intake of sugars4 and omega-6 poly-unsaturated fatty acids.5 However, the results presented by Shen and colleagues do not find an association. Most of the prior association studies were conducted in Caucasian populations in contrast to the study by Shen et al., which is derived from a biogeo-graphically distinct population compared with previous studies. However, the association between NAFLD and various metabolic traits was consistent across all previous studies, as well as this study, suggesting some generalis-ability between cohorts.6–10 Overall, the study provides four key messages. First, it confirms the association between PNPLA3 genotype and liver fat content by MRS in a Chinese population residing in Hong Kong. Second, PNPLA3 genotype effect on trait was not found to be influenced by diet in this study. Third, presence of metabolic syndrome trumps PNPLA3 genotype in it's association with the trait (i.e., NAFLD). Fourth, PNPLA3 genotype did not influence liver stiffness. These findings underscore the need to better understand the molecular mechanisms by which the GG variant is linked to fat accumulation in the liver, and further research is warranted to unravel the physiological role of the PNPLA3 in times of starvation and caloric excess. Improved understanding of the role of PNPLA3 could open new areas of investigations and may provide novel avenues for drug development and intervention studies to reverse NAFLD.

Polymorphism rs738409 in PNPLA3 is associated with inherited susceptibility to non-alcoholic fatty liver disease

To study the relationship between the patatin-like phospholipase domain-containing protein 3 (PNPLA3) gene and hereditary susceptibility to non-alcoholic fatty liver disease (NAFLD) by detecting single nucleotide polymorphisms (SNPs). Peripheral blood DNA from 315 patients diagnosed with NAFLD (including the spectrum of simple steatosis (SS) and non-alcoholic steatosis (NASH)) and 336 control subjects was used to determine the PNPLA3 genotype by polymerase chain reaction (PCR) and direct sequencing. The relationship of SNPs and NAFLD-related markers of liver function were assessed by correlation analysis. The SNP rs738409 was identified in more of the NAFLD patients (allele variant frequencies: NAFLD, 65.40%; NASH: 71.87%; SS, 56.47%) than in the controls (33.18%). Case-control analysis revealed that carriers of the 148GG genotype were at 3.81-fold (95% CI: 3.03 ~ 4.79) higher risk of developing NAFLD and at 1.97-fold (95% CI: 1.41 ~ 2.75) higher risk of progressing from SS to NASH, compared with non-carriers. rs738409 was also found to be associated with serum levels of alanine aminotransferase (ALT) and y-glutamyltransferase (y-GT) (both P less than 0.05). Carriers of the 148GG genotype had significantly higher body mass index, ALT, and fasting insulin than carriers of the 148CC genotype (all P less than 0.05), and significantly higher level of serum HDL than carriers of either the 148CC genotype or the 148GC genotype (both P less than 0.05). Polymorphisms in the PNPLA3 gene may play an important role in mediating susceptibility to developing NAFLD in the Chinese population. The rs738409 polymorphism, in particular, is related to development and progression of NAFLD and may play a role in the contribution of PNPLA3 to NAFLD pathogenesis.

Patatin-Like Phospholipase Domain-Containing Protein 3 rs738409-G in Recipients of Liver Transplants Is a Risk Factor for Graft Steatosis

The G-allele in position rs738409 of patatin-like phospholipase domain-containing protein 3 (PNPLA3) is associated with an increased hepatic concentration of triglyceride and is a risk factor for advanced liver disease. We investigated the association of donor and recipient risk alleles with the development of graft steatosis after liver transplantation. PNPLA3 genotypes were determined in 237 transplant recipients and in 255 organ donors. Macrovesicular steatosis was assessed by unenhanced computed tomography 5 years after liver transplantation in 95 patients and correlated with donor and recipient PNPLA3 genotype. The risk allele was significantly more frequent in transplant recipients than in donors (42% vs 28%; P < .001). A prevalence of graft steatosis of 30% or greater significantly increased from 11.6% at 1 year after liver transplantation to 32.6% at 5 years after transplantation. Five years after liver transplantation, steatosis was present in 63.2% of patients homozygous for the rs738409-G allele, in 31.4% of heterozygous recipients, and in 12.0% of rs738409-CC recipients (P = .002). Donor genotypes were not associated with the development of graft steatosis. In multivariate regression analysis, recipients who carried rs738409-GG had a 13.7-fold higher risk of graft steatosis than recipients who carried rs738409-CC (P = .022), independent of recipient age, weight gain after liver transplantation, or the underlying disease. Liver transplant recipients who carry rs738409-G in PNPLA3 are at increased risk for hepatic triglyceride accumulation, independent of the graft PNPLA3 genotype.

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

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

Genetic polymorphism in cyclooxygenase-2 promoter affects hepatic inflammation and fibrosis in patients with chronic hepatitis C

Cyclooxygenase (COX)-2 is involved in inflammation, anti-apoptosis and carcinogenesis. The -1195GG genotype of single nucleotide polymorphism (SNP) in COX-2 promoter was associated with low platelet counts in patients with chronic hepatitis C. Polymorphism of patatin-like phospholipase domain-containing protein 3 (PNPLA3) gene (rs738409 C>G) have been reported to be associated with cirrhosis, and the major genotype of SNPs near interleukin (IL)28B are related to viral clearance. The present study was designed to assess the contribution of these SNPs to disease progression in patients with chronic hepatitis C. The study enrolled 220 Japanese patients with chronic hepatitis C. Three SNPs, -1195 COX-2, PNPLA3 and IL28B (rs8099917), were genotyped in order to analyze their association with hepatic fibrosis and inflammation. The -1195GG genotype in COX-2 was associated with advanced fibrosis and higher levels of inflammation in the liver tissues. The major genotype of IL28B was also associated with advanced fibrosis, but the polymorphism of PNPLA3 was neither associated with fibrosis nor inflammation. Multivariate analysis showed that -1195GG in COX-2 is an independent factor associated with advanced fibrosis, while the major genotype of IL28B and HCV genotype 2 were other independent factors. In conclusion, the -1195GG genotype in COX-2 is a genetic marker for liver disease progression, while the PNPLA3 genotypes are not associated with disease progression in Japanese patients with chronic hepatitis C.