Evaluation of Polygenic Determinants of Non-Alcoholic Fatty Liver Disease (NAFLD) By a Candidate Genes Resequencing Strategy (original) (raw)
Related papers
Genetic variation in PNPLA3 confers susceptibility to nonalcoholic fatty liver disease
Nature Genetics, 2008
Nonalcoholic fatty liver disease (NAFLD) is a burgeoning health problem of unknown etiology that varies in prevalence among ancestry groups. To identify genetic variants contributing to differences in hepatic fat content, we carried out a genome-wide association scan of nonsynonymous sequence variations (n = 9,229) in a population comprising Hispanic, African American and European American individuals. An allele in PNPLA3 (rs738409[G], encoding I148M) was strongly associated with increased hepatic fat levels (P = 5.9 × 10 −10 ) and with hepatic inflammation (P = 3.7 × 10 −4 ). The allele was most common in Hispanics, the group most susceptible to NAFLD; hepatic fat content was more than twofold higher in PNPLA3 rs738409[G] homozygotes than in noncarriers. Resequencing revealed another allele of PNPLA3 (rs6006460[T], encoding S453I) that was associated with lower hepatic fat content in African Americans, the group at lowest risk of NAFLD. Thus, variation in PNPLA3 contributes to ancestry-related and inter-individual differences in hepatic fat content and susceptibility to NAFLD.
Genetics of nonalcoholic fatty liver disease in Asian populations
Journal of Genetics, 2018
Nonalcoholic fatty liver disease (NAFLD) is characterized by the accumulation of fat in the liver without any history of chronic alcohol consumption. It encompasses a wide spectrum of diseases that range from simple steatosis to nonalcoholic steatohepatitis. NAFLD is strongly associated with obesity, insulin resistance / type-2 diabetes mellitus and the metabolic syndrome. NAFLD is a complex disorder; environmental and genetic factors interact with NAFLD manifestation and determine its progression. In this review, an attempt was made to provide current information on the genetic variants of NAFLD in Asian populations. Literature search was performed by using PubMed, Medline and Google Scholar database. Candidate gene, validation and genomewide association studies (GWASs) were included in this review. A total of 41 studies fulfilled inclusion criteria of which 12 candidate gene studies exclusively focussed on the PNPLA3 gene and 17 other studies on other important candidate genes such as NCAN-CILP2, PPARG, AGTR1, FABP1, APOC3 etc. reported significant association with NAFLD. Eight validation studies identified associations of variants on PNPLA3, LYPLAL1, TM6SF2, ADIPOR2, STAT3, GCKR, SAMM50 etc. with NAFLD. Thus, so far, four GWASs have been conducted in Asian population that reported PNPLA3, SAMM50, PARVB and GATAD2A genes which were significantly associated with NAFLD. Findings indicate that PNPLA3, APOC3, PPARG, NCAN and GCKR genes emerge out to be the important biological markers associated with NAFLD.
Human genetics, 2012
The adiponutrin (PNPLA3) rs738409 polymorphism has been found to be associated with susceptibility to non-alcoholic fatty liver disease (NAFLD) in various cohorts. We further investigated the association of this polymorphism with non-alcoholic steatohepatitis (NASH) severity and with histological features of NAFLD. A total of 144 biopsy-proven NAFLD patients and 198 controls were genotyped for PNPLA3 gene polymorphism (rs738409 C>G). The biopsy specimens were histologically graded by a qualified pathologist. We observed an association of G allele with susceptibility to NAFLD in the pooled subjects (OR 2.34, 95% CI 1.69-3.24, p < 0.0001), and following stratification, in each of the three ethnic subgroups, namely Chinese, Indian and Malay (OR 1.94, 95% CI 1.12-3.37, p = 0.018; OR 3.51, 95% CI 1.69-7.26, p = 0.001 and OR 2.05, 95% CI 1.25-3.35, p = 0.005, respectively). The G allele is associated with susceptibility to NASH (OR 2.64, 95% CI 1.85-3.75, p < 0.0001), with NASH severity (OR 1.85, 95% CI 1.05-3.26, p = 0.035) and with presence of fibrosis (OR 1.95, 95% CI 1.17-3.26, p = 0.013) but not with simple steatosis nor with other histological parameters. Although the serum triglyceride level is significantly higher in NAFLD patients compared to controls, the G allele is associated with decreased level of triglycerides (p = 0.029) in the NAFLD patients. Overall, the rs738409 G allele is associated with severity of NASH and occurence of fibrosis in patients with NAFLD. © 2012 The Author(s).
Hepatology International
Objective Several single-nucleotide polymorphisms have been identified to be disadvantageous or protective in regard to disease severity in patients with non-alcoholic fatty liver disease (NAFLD). However, it is unclear, whether including genetic risk factor(s) either alone or combined into risk stratification algorithms for NAFLD actually provides incremental benefit over clinical risk factors. Design Patients with biopsy-proven NAFLD were genotyped for the PNPLA3-rs738409(minor allele:G), TM6SF2-rs58542926(minor allele:T) and HSD17B13- rs72613567 (minor allele:TA) variants. The NAFLD activity score (NAS) and fibrosis stage (F0–F4) were used to grade and stage all liver biopsy samples. Patients from seven centers throughout Central Europe were considered for the study. Results 703 patients were included: NAS ≥ 5:173(24.6%); Fibrosis: F3–4:81(11.5%). PNPLA3 G/G genotype was associated with a NAS ≥ 5(aOR 2.23, p = 0.007) and advanced fibrosis (aOR-3.48, p
Human Genetics, 2013
We examined the genetic background of nonalcoholic fatty liver disease (NAFLD) in the Japanese population, by performing a genome-wide association study (GWAS). For GWAS, 372 Japanese NAFLD subjects and 934 control individuals were analyzed. For replication studies, 172 NAFLD and 1012 control subjects were monitored. After quality control, 261,540 single-nucleotide polymorphisms (SNPs) in autosomal chromosomes were analyzed by using a trend test. Association analysis was also performed by using multiple logistic regression analysis using genotypes, age, gender and body mass index (BMI) as independent variables. Multiple linear regression analyses were performed to evaluate allelic effect of significant SNPs on biochemical traits and histological parameters adjusted by age, gender, and BMI. Rs738409 in the PNPLA3 gene was most strongly associated with NAFLD after adjustment (P = 6.8 × 10-14 , odds ratio = 2.05). Rs2896019, and rs381062 in the PNPLA3 gene, rs738491, rs3761472, and rs2143571 in the SAMM50 gene, rs6006473, rs5764455, and rs6006611 in the PARVB gene had also significant P-values (<2.0 × 10-10) and high odds ratios (1.84 to 2.02). These SNPs were found to be in the same linkage disequilibrium block and were associated with decreased serum triglycerides and increased aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in NAFLD patients. These SNPs were associated with steatosis grade and NAFLD activity score (NAS). Rs738409, rs2896019, rs738491, rs6006473, rs5764455, 2 and rs6006611 were associated with fibrosis. Polymorphisms in the SAMM50 and PARVB genes in addition to those in the PNPLA3 gene were observed to be associated with the development and progression of NAFLD.
Genetic and metabolic aspects of non-alcoholic fatty liver disease (NAFLD) pathogenicity
Egyptian Journal of Medical Human Genetics
Background Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease showing a rising prevalence globally. Genetic predisposition plays a key role in the development and progression of the disease pathogenicity. Main body This paper summarizes genetic associations based on their influence on several metabolic aspects such as lipid metabolism, glucose metabolism, hepatic iron accumulation and cholesterol metabolism toward the NAFLD pathogenicity. Furthermore, we present variations in some epigenetic characters and the microRNA profile with regard to NAFLD. Conclusion As reported in many studies, the PNPLA3 rs738409 variant seems to be significantly associated with NAFLD susceptibility. Other gene variants like TM6SF2 rs58542926, MBOAT7 rs641738 and GCKR variants also appear to be more prevalent among NAFLD patients. We believe these genetic variants may provide insights into new trends in developing noninvasive biomarkers and identify their suitability in cli...
World Journal of Gastroenterology, 2009
The spectrum of non-alcoholic fatty liver disease (NAFLD) ranges from simple steatosis through steatohepatitis to advanced fibrosis and cirrhosis. Although the reason why only a minority of patients develop progressive forms of disease still remains largely unclear, recent research has identified genetic factors as a possible basis for this variation in disease presentation. Most of the studies have been focused on finding associations between advanced disease forms and selected single nucleotide polymorphisms in genes encoding various proteins involved in disease pathogenesis. Although there are many limitations regarding the study design and interpretation of published data, further carefully planned studies together with implementation of new genetic technologies will likely bring new insights into disease pathogenesis and potential benefits to the management of patients with NAFLD.
Scientific Reports
Current knowledge on the genetic basis of nonalcoholic fatty liver disease (NAFLD) suggests that variants contributing not only to the disease predisposition but histological severity as well are located in genes that regulate lipid metabolism. We explored the role of rs641738 C/T located in TMC4 (transmembrane channel-like 4) exon 1 (p.Gly17Glu) and 500 bases-downstream of MBOAT7 gene (TMC4/MBOAT7), in the genetic risk for developing NAFLD in a case-control study. Our sample included 634 individuals (372 patients with NAFLD diagnosed by liver biopsy and 262 control subjects); genotyping was performed by a Taqman assay. Genotype frequencies in controls (CC: 84, CT: 137, TT: 41) and patients (CC: 134, CT: 178, TT: 60) were in Hardy-Weinberg equilibrium; minor allele frequency 40.8%. Our sample had 84-99% power if an additive genetic model is assumed for estimated odds ratios of 1.3-1.5, respectively. We found no evidence of association between rs641738 and either NAFLD (Cochran-Armitage test for trend, p = 0.529) or the disease severity (p = 0.61). Low levels of MBOAT7 protein expression were found in the liver of patients with NAFLD, which were unrelated to the rs641738 genotypes. In conclusion, the role of rs641738 in the pathogenesis of NAFLD is inconclusive. Current understanding of the genetic basis of nonalcoholic fatty liver disease (NAFLD) suggests that variants contributing not only to the disease susceptibility but also histological severity are located in genes that regulate lipid metabolism. Specifically, the missense p.Ile148Met (rs738409) variant located in PNPLA3 (patatin-like phospholipase domain-containing 3) has been consistently associated with increased liver fat content and NAFLD severity, including fibrosis, across different populations around the world 1-3. The risk effect of rs738409 on developing NAFLD is the strongest ever reported for a common variant modifying the genetic susceptibility of the
Genetic background in nonalcoholic fatty liver disease: A comprehensive review
World Journal of Gastroenterology, 2015
In the Western world, nonalcoholic fatty liver disease (NAFLD) is considered as one of the most significant liver diseases of the twenty-first century. Its development is certainly driven by environmental factors, but it is also regulated by genetic background. The role of heritability has been widely demonstrated by several epidemiological, familial, and twin studies and case series, and likely reflects the wide interindividual and inter-ethnic genetic variability in systemic metabolism and wound healing response processes. Consistent with this idea, genome-wide association studies have clearly identified Patatin-like phosholipase domain-containing 3 gene variant I148M as a major player in the development and progression of NAFLD. More recently, the transmembrane 6 superfamily member 2 E167K variant emerged as a relevant contributor in both NAFLD pathogenesis and cardiovascular outcomes. Furthermore, numerous casecontrol studies have been performed to elucidate the potential role of candidate genes in the pathogenesis and progression of fatty liver, although findings are sometimes contradictory. Accordingly, we performed a comprehensive literature search and review on the role of genetics in NAFLD. We emphasize the strengths and weaknesses of the available literature and outline the putative role of each genetic variant in influencing susceptibility and/or progression of the disease.
Nutritional Genomics in Nonalcoholic Fatty Liver Disease
Biomedicines
Nonalcoholic fatty liver disease (NAFLD) is a common chronic condition associated with genetic and environmental factors in which fat abnormally accumulates in the liver. NAFLD is epidemiologically associated with obesity, type 2 diabetes, and dyslipidemia. Environmental factors, such as physical inactivity and an unbalanced diet, interact with genetic factors, such as epigenetic mechanisms and polymorphisms for the genesis and development of the condition. Different genetic polymorphisms seem to be involved in this context, including variants in PNPLA3, TM6SF2, PEMT, and CHDH genes, playing a role in the disease’s susceptibility, development, and severity. From carbohydrate intake and weight loss to omega-3 supplementation and caloric restriction, different dietary and nutritional factors appear to be involved in controlling the onset and progression of NAFLD conditions influencing metabolism, gene, and protein expression. The polygenic risk score represents a sum of trait-associat...