Allele HLA-DQB1*06 reduces fibrosis score in patients with non-alcoholic fatty liver disease.

AIM: Human leukocyte antigen (HLA) regions were highlighted as important genetic markers for various liver diseases by hepatology-related genome-wide association studies. Replication studies in non-alcoholic fatty liver disease (NAFLD) are limited and none has investigated the association of HLA alleles with non-alcoholic steatohepatitis (NASH) and other histological characteristics. In the current study, we examined the association of HLA-DQA1 and HLA-DQB1 alleles with NAFLD spectrum and its histological characteristics. METHODS: Consecutive biopsy-proven NAFLD patients (n = 191) and healthy controls (n = 188) were enrolled and genotyped for HLA-DQA1 and HLA-DQB1 alleles using the sequence-specific oligonucleotide-polymerase chain reaction method. RESULTS: No association was found between the HLA alleles and NAFLD or NASH in a case-control setting. Nevertheless, among NAFLD patients, the frequency of HLA-DQB1*06 allele was significantly the lowest in NASH with significant fibrosis (10.4%) and approximately similar for NASH without significant fibrosis (22.9%) and NAFL (22.5%) (P = 0.004). It is noteworthy that the association remains significant after correction for multiple comparisons (Pc = 0.04). Multivariate analysis revealed that HLA-DQB1*06 allele is also associated with fibrosis score (P = 0.001); the result remains significant after correction for multiple comparisons. CONCLUSION: These findings suggest that HLA-DQB1*06 is associated with lower fibrosis score in NAFLD patients.

Phosphatidylethanolamine N-methyltransferase gene rs7946 polymorphism plays a role in risk of nonalcoholic fatty liver disease: evidence from meta-analysis.

BACKGROUND: Phosphatidylethanolamine N-methyltransferase (PEMT) governs the secretion of hepatic triglycerides in the form of very low-density lipoprotein and has been implicated in nonalcoholic fatty liver disease (NAFLD). Studies on the role of the PEMT rs7946 polymorphism as a genetic modifier of NAFLD have reported inconsistent results. This meta-analysis was carried out to evaluate and summarize the association of PEMT rs7946 with susceptibility to NAFLD. METHODS: A comprehensive literature search in Scopus, PubMed, Embase, Science Direct and Google Scholar was performed up to 31 August 2015, followed by data extraction and examination of summary estimates. RESULTS: Six independent studies with a total of 792 NAFLD cases and 2722 controls fulfilled the inclusion criteria. Pooled results indicated that the rs7946 A-allele was associated significantly with an increased risk of NAFLD [odds ratio (OR) 1.55, 95% confidence interval (CI) 1.14-2.11, P=0.005]. A significant association was also found in alternative genetic models of inheritance: dominant, recessive and homozygote (OR 1.62, 95% CI 1.10-2.39, P=0.01; OR 1.42, 95% CI 1.12-1.81, P=0.003; and OR 1.64, 95% CI 1.18-2.29, P=0.004, respectively). Subgroup analysis by ethnicity indicated a significant association only in the East-Asians in the additive (OR=2.08, 95% CI 1.12-3.86, P=0.02), recessive (OR=2.94, 95% CI 1.60-5.37, P=0.0005) and homozygote (OR=1.86, 95% CI 1.15-3.01, P=0.01) models. CONCLUSION: This study provides evidence of a significant association between the PEMT rs7946 A-allele and a risk of NAFLD, with the effect being more prominent in East-Asians, but not in non-Asians.

Impact of leptin receptor gene variants on risk of non-alcoholic fatty liver disease and its interaction with adiponutrin gene.

BACKGROUND AND AIM: Genetic polymorphism has been implicated as a factor for the occurrence of non-alcoholic fatty liver disease (NAFLD). This study attempted to assess whether polymorphisms in the leptin receptor (LEPR) gene and its combined effect with patatin-like phospholipase domain-containing protein 3 (PNPLA3/adiponutrin) are associated with risk of NAFLD. METHODS: A total of 144 biopsy-proven NAFLD and 198 controls were genotyped using the Sequenom MassARRAY platform. RESULTS: We observed a significant association between the LEPR rs1137100 and rs1137101 with susceptibility to NAFLD (odds ratio [OR] 1.64, 95% confidence interval [CI] 1.18-2.28, P = 0.003; and OR 1.61, 95% CI 1.11-2.34, P = 0.013, respectively) and to non-alcoholic steatohepatitis (OR 1.49, 95% CI 1.05-2.12, P = 0.026; and OR 1.57, 95% CI 1.05-2.35, P = 0.029, respectively). The LEPR rs1137100 is also associated with simple steatosis (OR 2.27, 95% CI 1.27-4.08, P = 0.006). Analysis of gene-gene interaction revealed a strong interaction between the LEPR and PNPLA3 genes (empirical P = 0.001). The joint effect of LEPR and PNPLA3 greatly exacerbated the risk of NAFLD (OR 3.73, 95% CI 1.84-7.55, P < 0.0001). The G allele of rs1137100 is associated with lower fibrosis score (OR 0.47, 95% CI 0.28-0.78, P = 0.001). CONCLUSIONS: We report an association between variants of LEPR rs1137100 and rs1137101 with risk of NAFLD. This study suggests that rs1137100, specifically the G allele, is associated with a less severe form of liver disease in patients with NAFLD. The interaction between LEPR and PNPLA3 genes showed increased risk of NAFLD compared to either gene alone.

Loss-of-function HSD17B13 variants, non-alcoholic steatohepatitis and adverse liver outcomes: Results from a multi-ethnic Asian cohort.

BACKGROUND/AIMS: 17ß-hydroxysteroid dehydrogenase 13 (HSD17B13) variants were recently reported to have significantly lower odds of non-alcoholic fatty liver disease (NAFLD). This is a two-part study that aimed to evaluate the association of HSD17B13 variants with NAFLD and its histological severity, and to identify the association of the variants with clinical outcomes in a cohort of biopsy-proven NAFLD patients. METHODS: Consecutive biopsy-proven NAFLD patients and controls without fatty liver were recruited for this study between 2009 and 2014. Genotyping for HSD17B13 variants was performed using rhAmp assays. A total of 165 patients with NAFLD were monitored up until August 2019. Clinical outcomes were recorded. RESULTS: HSD17B13 rs72613567 TA allele and rs6834314 G allele were associated with lower odds of non-alcoholic steatohepatitis (NASH) in the overall cohort and among ethnic Chinese, but not among ethnic Malays or Indians (P<0.05). During a mean follow-up of 89 months, 32 patients (19.4%) experienced at least one clinical outcome (cardiovascular events, n=22; liver-related complications, n=6; extra-hepatic malignancy, n=5; and mortality, n=6). The rs72613567 homozygous TA allele and the rs6834314 homozygous G allele were independently associated with a lower incidence of liver-related complications (hazard ratio [HR], 0.004; 95% confidence interval [CI], 0.00-0.64; P=0.033 and HR, 0.01; 95% CI, 0.00-0.97; P=0.048, respectively) and were associated with lower grade of hepatocyte ballooning among the ethnic Chinese. CONCLUSION: HSD17B13 rs72613567 and rs6834314 variants were inversely associated with NAFLD and NASH, and were associated with lower incidence of adverse liver outcomes in a cohort of multi-ethnic Asian patients with NAFLD.

Use of simple scoring systems for a public health approach in the management of non-alcoholic fatty liver disease patients.

BACKGROUND AND AIM: Advanced fibrosis is the most important predictor of liver-related mortality in non-alcoholic fatty liver disease (NAFLD). The aim of this study was to compare the diagnostic performance of noninvasive scoring systems in identifying advanced fibrosis in a Malaysian NAFLD cohort and propose a simplified strategy for the management of NAFLD in a primary care setting. METHODS: We enrolled and reviewed 122 biopsy-proven NAFLD patients. Advanced fibrosis was defined as fibrosis stages 3-4. Noninvasive assessments included aspartate aminotransferase/alanine aminotransferase (AST/ALT) ratio, AST-to-platelet ratio index (APRI), AST/ALT ratio, diabetes (BARD) score, fibrosis-4 (FIB-4) score, and NAFLD fibrosis score. RESULTS: FIB-4 score had the highest area under the receiver operating characteristic curve (AUROC) and negative predictive value (NPV) of 0.86 and 94.3%, respectively, for the diagnosis of advanced fibrosis. FIB-4 score < 1.3 ruled out advanced fibrosis in 72% of the patients, with 6% being understaged. Further stratification of the indeterminate group patients by other non-alcoholic steatohepatitis (NASH) clinical predictors, such as abnormal gamma-glutamyl transpeptidase (GGT) level and presence diabetes mellitus (DM), could further reduce the number of patients who are unlikely to have advanced fibrosis by 52% and 35%, respectively. CONCLUSION: We found that FIB-4 score outperforms other scoring systems based on AUROC and NPV. The use of a simple scoring system such as FIB-4 as first-line triage to risk-stratify NAFLD patients in the primary care setting, with further stratification of those in the indeterminate group using clinical predictors of NASH, can help in the development of a simplified strategy for a public health approach in the management of NAFLD.

Copy number variation in exportin-4 (XPO4) gene and its association with histological severity of non-alcoholic fatty liver disease.

A recent genome-wide copy number (CNV) scan identified a 13q12.11 duplication in the exportin-4 (XPO4) gene to be associated with non-alcoholic steatohepatitis (NASH). We sought to confirm the finding in a larger cohort and to assess the serum XPO4 pattern in a broad spectrum of non-alcoholic fatty liver disease (NAFLD) cases. We analysed 249 NAFLD patients and 232 matched controls using TaqMan assay and serum XPO4 was measured. Copy number distribution was as follows: copy number neutral (NAFLD: 53.8%, controls: 68.6%), copy number losses (NAFLD: 13.3%, controls: 12.9%), copy number gains (NAFLD: 32.9%, controls: 18.5%). CNV gain was significantly associated with a greater risk of NAFLD (adjusted OR 2.22, 95% CI 1.42-3.46, P = 0.0004) and NASH (adjusted OR 2.33, 95% CI 1.47-3.68, P = 0.0003). Interestingly, subjects carrying extra copy number showed significantly higher serum ALT and triglyceride (P < 0.05). Serum XPO4 levels progressively declined (P = 0.043) from controls (24.6 ng/mL) to simple steatosis (20.8 ng/mL) to NASH (13.8 ng/mL). In conclusion, XPO4 CNV duplication was associated with histological severity of NAFLD, and accompanied by changes in serum XPO4 levels providing insights into NAFLD pathogenesis, and has the potential for biomarker development.

Association of glucokinase regulatory gene polymorphisms with risk and severity of non-alcoholic fatty liver disease: an interaction study with adiponutrin gene.

BACKGROUND: Recent genome-wide association studies demonstrated an association between single nucleotide polymorphisms (SNPs) on the glucokinase regulatory gene (GCKR) with hepatic steatosis. This study attempted to investigate the association of GCKR rs780094 and rs1260326 with susceptibility to non-alcoholic fatty liver disease (NAFLD) and its severity. METHODS: The genotypes were assessed on 144 histologically confirmed NAFLD patients and 198 controls using a Sequenom MassARRAY platform. RESULTS: The GCKR rs1260326 and rs780094 allele T were associated with susceptibility to NAFLD (OR 1.49, 95 % CI 1.09-2.05, p = 0.012; and OR 1.51, 95 % CI 1.09-2.09, p = 0.013, respectively), non-alcoholic steatohepatitis (NASH) (OR 1.55, 95 % CI 1.10-2.17, p = 0.013; and OR 1.56, 95 % CI 1.10-2.20, p = 0.012, respectively) and NASH with significant fibrosis (OR 1.50, 95 % CI 1.01-2.21, p = 0.044; and OR 1.52, 95 % CI 1.03-2.26, p = 0.038, respectively). Following stratification by ethnicity, significant association was seen in Indian patients between the two SNPs and susceptibility to NAFLD (OR 2.64, 95 % CI 1.28-5.43, p = 0.009; and OR 4.35, 95 % CI 1.93-9.81, p < 0.0001, respectively). The joint effect of GCKR with adiponutrin rs738409 indicated greatly increased the risk of NAFLD (OR 4.14, 95 % CI 1.41-12.18, p = 0.010). Histological data showed significant association of GCKR rs1260326 with high steatosis grade (OR 1.76, 95 % CI 1.08-2.85, p = 0.04). CONCLUSION: This study suggests that risk allele T of the GCKR rs780094 and rs1260326 is associated with predisposition to NAFLD and NASH with significant fibrosis. The GCKR and PNPLA3 genes interact to result in increased susceptibility to NAFLD.