Identification and characterisation of a rare MTTP variant underlying hereditary non-alcoholic fatty liver disease

Background and aimsNon-alcoholic fatty liver disease (NAFLD) is a complex trait with an estimated prevalence of 25% globally. We aimed to identify the genetic variant underlying a four-generation family with progressive NAFLD leading to cirrhosis, decompensation and development of hepatocellular carcinoma in the absence of common risk factors such as obesity and type 2 diabetes.MethodsExome sequencing and genome comparisons were used to identify the likely causal variant. We extensively characterised the clinical phenotype and post-prandial metabolic responses of family members with the identified novel variant in comparison to healthy non-carriers and wild-type patients with NAFLD. Variant-expressing hepatocyte-like cells (HLCs) were derived from human induced pluripotent stem cells generated from homozygous donor skin fibroblasts and restored to wild-type using CRISPR-Cas9. The phenotype was assessed using imaging, targeted RNA analysis and molecular expression arrays.ResultsWe identified a rare causal variant c.1691T>C p.I564T (rs745447480) in MTTP, encoding microsomal triglyceride transfer protein (MTP), associated with progressive NAFLD, unrelated to metabolic syndrome and without characteristic features of abetalipoproteinemia. HLCs derived from a homozygote donor had significantly lower MTP activity and lower lipoprotein ApoB secretion compared to wild-type cells, while having similar levels of MTP mRNA and protein. Cytoplasmic triglyceride accumulation in HLCs triggered endoplasmic reticulum stress, secretion of pro-inflammatory mediators and production of reactive oxygen species.ConclusionWe have identified and characterized a rare causal variant in MTTP and homozygosity for MTTP p.I564T is associated with progressive NAFLD without any other manifestations of abetalipoproteinemia. Our findings provide insights into mechanisms driving progressive NAFLD

Comparison of patient sensitivity using dentin bonding agent versus zinc phosphate base beneath the amalgam restorations: An in vivo comparative study

Aim: The aim of the present study is to evaluate and compare patient sensitivity following the amalgam restorations using two different materials beneath them - zinc phosphate base and dentin bonding agent. Materials and Methods: Thirty individuals aged between 20 years and 60 years were selected who presented with two class I carious lesions located in different quadrants. Both the teeth were filled at the same appointment. Following rubber dam isolation, conventional cavities were prepared for the amalgam restorations. One tooth received zinc phosphate base while the other received dentin bonding agent beneath the amalgam restoration. High copper non-γ2 amalgam was triturated using amalgamator by condensing it into the cavity. Questionnaires were given to the patients for recording sensitivity scores to heat, cold, or biting at the end of 1, 3, 7, and 14 days. Results: Significance was determined based on the P values obtained from the simple curve z-test. On day 1, when groups I and II were compared, no significant difference in number of patients reporting postoperative sensitivity was found. On day 3, more number of patients reported sensitivity with zinc phosphate cement compared to those with dentin bonding agent. On day 7, there was great reduction in sensitivity in both groups compared to day 1 and day 3 but comparatively more in teeth with zinc phosphate base. On day 14, there was no significant sensitivity in both groups, patients showing no sensitivity to both zinc phosphate base and dentin bonding agent. Conclusion: Postoperative sensitivity was relatively more in teeth restored with zinc phosphate base compared to that restored with dentin bonding agent. Postoperative sensitivity resolved earlier in restorations with dentin bonding agent compared to zinc phosphate base, and sensitivity resolved with time in both the restorations

Corrigendum to ‘An international genome-wide meta-analysis of primary biliary cholangitis: Novel risk loci and candidate drugs’ [J Hepatol 2021;75(3):572–581] (Journal of Hepatology (2021) 75(3) (572–581), (S0168827821003342), (10.1016/j.jhep.2021.04.055))

It has come to our attention that the name of one of the authors in our manuscript was incorrectly spelled ‘Jinyoung Byan’; the correct spelling is ‘Jinyoung Byun’ as in the author list above. In addition, the excel files of the supplementary tables were not included during the online publication of our article. These have now been made available online. We apologize for any inconvenience caused

Corrigendum to \u2018An international genome-wide meta-analysis of primary biliary cholangitis: Novel risk loci and candidate drugs\u2019 [J Hepatol 2021;75(3):572\u2013581] (Journal of Hepatology (2021) 75(3) (572\u2013581), (S0168827821003342), (10.1016/j.jhep.2021.04.055))

It has come to our attention that the name of one of the authors in our manuscript was incorrectly spelled \u2018Jinyoung Byan\u2019; the correct spelling is \u2018Jinyoung Byun\u2019 as in the author list above. In addition, the excel files of the supplementary tables were not included during the online publication of our article. These have now been made available online. We apologize for any inconvenience caused

An international genome-wide meta-analysis of primary biliary cholangitis: Novel risk loci and candidate drugs.

BACKGROUNDS & AIMS Primary biliary cholangitis (PBC) is a chronic liver disease in which autoimmune destruction of the small intrahepatic bile ducts eventually leads to cirrhosis. Many patients have inadequate response to licensed medications, motivating the search for novel therapies. Previous genome-wide association studies (GWAS) and meta-analyses (GWMA) of PBC have identified numerous risk loci for this condition, providing insight into its aetiology. We undertook the largest GWMA of PBC to date, aiming to identify additional risk loci and prioritise candidate genes for in silico drug efficacy screening. METHODS We combined new and existing genotype data for 10,516 cases and 20,772 controls from 5 European and 2 East Asian cohorts. RESULTS We identified 56 genome-wide significant loci (20 novel) including 46 in European, 13 in Asian, and 41 in combined cohorts; and a 57 genome-wide significant locus (also novel) in conditional analysis of the European cohorts. Candidate genes at newly identified loci include FCRL3, INAVA, PRDM1, IRF7, CCR6, CD226, and IL12RB1, which each play key roles in immunity. Pathway analysis reiterated the likely importance of pattern recognition receptor and TNF signalling, JAK-STAT signalling, and differentiation of T helper (T)1 and T17 cells in the pathogenesis of this disease. Drug efficacy screening identified several medications predicted to be therapeutic in PBC, some of which are well-established in the treatment of other autoimmune disorders. CONCLUSIONS This study has identified additional risk loci for PBC, provided a hierarchy of agents that could be trialled in this condition, and emphasised the value of genetic and genomic approaches to drug discovery in complex disorders. LAY SUMMARY Primary biliary cholangitis (PBC) is a chronic liver disease that eventually leads to cirrhosis. In this study, we analysed genetic information from 10,516 people with PBC and 20,772 healthy individuals recruited in Canada, China, Italy, Japan, the UK, or the USA. We identified several genetic regions associated with PBC. Each of these regions contains several genes. For each region, we used diverse sources of evidence to help us choose the gene most likely to be involved in causing PBC. We used these 'candidate genes' to help us identify medications that are currently used for treatment of other conditions, which might also be useful for treatment of PBC