Telomere length and risk of cirrhosis, hepatocellular carcinoma, and cholangiocarcinoma in 63,272 individuals from the general population.

BACKGROUND AND AIMS: Inherited short telomeres are associated with a risk of liver disease, whereas longer telomeres predispose to cancer. The association between telomere length and risk of HCC and cholangiocarcinoma remains unknown. APPROACH AND RESULTS: We measured leukocyte telomere length using multiplex PCR in 63,272 individuals from the Danish general population. Telomere length and plasma ALT concentration were not associated (ß = 4 ×10 -6 , p -value = 0.06) in a linear regression model, without any signs of a nonlinear relationship. We tested the association between telomere length and risk of cirrhosis, HCC, and cholangiocarcinoma using Cox regression. During a median follow-up of 11 years, 241, 76, and 112 individuals developed cirrhosis, HCC, and cholangiocarcinoma, respectively. Telomere length and risk of cirrhosis were inversely and linearly associated ( p -value = 0.004, p for nonlinearity = 0.27). Individuals with telomeres in the shortest vs. longest quartile had a 2.25-fold higher risk of cirrhosis. Telomere length and risk of HCC were nonlinearly associated ( p -value = 0.009, p -value for nonlinearity = 0.01). This relationship resembled an inverted J-shape, with the highest risk observed in individuals with short telomeres. Individuals with telomeres in the shortest versus longest quartile had a 2.29-fold higher risk of HCC. Telomere length was inversely and linearly associated with the risk of cholangiocarcinoma. Individuals with telomeres in the shortest versus longest quartile had a 1.86-fold higher risk of cholangiocarcinoma. CONCLUSIONS: Shorter telomere length is associated with a higher risk of cirrhosis, HCC, and cholangiocarcinoma.

Genetic risk of fatty liver disease and mortality in the general population: A Mendelian randomization study.

BACKGROUND & AIMS: Fatty liver disease has been associated with higher all-cause as well as liver-related, ischemic heart disease (IHD)-related and extrahepatic cancer-related mortality in observational epidemiological studies. We tested the hypothesis that fatty liver disease is a causal risk factor for higher mortality. METHODS: We genotyped seven genetic variants known to be associated with fatty liver disease (in PNPLA3, TM6SF2, HSD17B13, MTARC1, MBOAT7, GCKR, and GPAM) in 110 913 individuals from the Danish general population. Hepatic steatosis was measured by hepatic computed tomography in n = 6965. Using a Mendelian randomization framework, we tested whether genetically proxied hepatic steatosis and/or elevated plasma alanine transaminase (ALT) was associated with liver-related mortality. RESULTS: During a median follow-up of 9.5 years, 16 119 individuals died. In observational analyses, baseline elevated plasma ALT was associated with higher all-cause (1.26-fold), liver-related (9-fold), and extrahepatic cancer-related (1.25-fold) mortality. In genetic analyses, the risk alleles in PNPLA3, TM6SF2, and HSD17B13 were individually associated with higher liver-related mortality. The largest effects were seen for the PNPLA3 and TM6SF2 risk alleles, for which homozygous carriers had 3-fold and 6-fold, respectively, higher liver-related mortality than non-carriers. None of the risk alleles, individually or combined into risk scores, were robustly associated with all-cause, IHD-related, or extrahepatic cancer-related mortality. In instrumental variable analyses, genetically proxied hepatic steatosis and higher plasma ALT were associated with liver-related mortality. CONCLUSIONS: Human genetic data support that fatty liver disease is a causal driver of liver-related mortality.

An adult-based genetic risk score for liver fat associates with liver and plasma lipid traits in children and adolescents.

BACKGROUND & AIMS: Genome-wide association studies have identified steatogenic variants that also showed pleiotropic effects on cardiometabolic traits in adults. We investigated the effect of eight previously reported genome-wide significant steatogenic variants, individually and combined in a weighted genetic risk score (GRS), on liver and cardiometabolic traits, and the predictive ability of the GRS for hepatic steatosis in children and adolescents. APPROACH & RESULTS: Children and adolescents with overweight (including obesity) from an obesity clinic group (n = 1768) and a population-based group (n = 1890) were included. Cardiometabolic risk outcomes and genotypes were obtained. Liver fat was quantified using 1 H-MRS in a subset of 727 participants. Variants in PNPLA3, TM6SF2, GPAM and TRIB1 were associated with higher liver fat (p < .05) and with distinct patterns of plasma lipids. The GRS was associated with higher liver fat content, plasma concentrations of alanine transaminase (ALT), aspartate aminotransferase (AST) and favourable plasma lipid levels. The GRS was associated with higher prevalence of hepatic steatosis (defined as liver fat ≥5.0%) (odds ratio per 1-SD unit: 2.17, p = 9.7E-10). A prediction model for hepatic steatosis including GRS alone yielded an area under the curve (AUC) of 0.78 (95% CI 0.76-0.81). Combining the GRS with clinical measures (waist-to-height ratio [WHtR] SDS, ALT, and HOMA-IR) increased the AUC up to 0.86 (95% CI 0.84-0.88). CONCLUSIONS: The genetic predisposition for liver fat accumulation conferred risk of hepatic steatosis in children and adolescents. The liver fat GRS has potential clinical utility for risk stratification.

Metabolic and Genetic Risk Factors Are the Strongest Predictors of Severity of Alcohol-Related Liver Fibrosis.

BACKGROUND & AIMS: Individual risk for developing alcohol-related liver disease (ALD) varies greatly. We hypothesized that metabolic risk factors and genetic polymorphisms predict severity of ALD. METHODS: Biopsy-controlled, cross-sectional study in patients with a history of excessive drinking. We measured the homeostatic model assessment of insulin resistance (HOMA-IR), plasma triglycerides, high- and low-density lipoproteins (HDL, LDL), and total cholesterol. Moreover, we genotyped four single nucleotide polymorphisms in PNPLA3 (rs738409C>G), TM6SF2 (rs58542926C>T), MBOAT7 (rs641738C>T), and HSD17B13 (rs72613567T>TA). We assessed predictors of higher fibrosis stage using multivariable ordered logistic regression. RESULTS: Of 325 included patients, 25% had severe fibrosis or cirrhosis and 59% had HOMA-IR ≥2.5. HOMA-IR increased for each fibrosis stage, while there was a similar decrease in LDL and total cholesterol. Individuals with risk variant PNPLA3 rs738409-G or TM6SF2 rs58542926-T had higher fibrosis stage. In multivariable regression, HOMA-IR ≥2.5 (OR = 3.04, 95% CI 1.90-4.87), LDL <2.60 mmol/L (OR = 2.05, 95% CI 1.33-3.16), TM6SF2 rs58542926-T (OR = 1.99, 95% CI 1.17-3.37), age above 50 years (OR = 1.66, 95% CI 1.03-2.70), and PNPLA3 rs738409-G (OR = 1.54, 95% CI 1.11-2.12) independently predicted higher fibrosis stage. Independent predictors of hepatic inflammatory activity were HOMA-IR, active drinking, age, and PNPLA3 risk variant. Active drinking, elevated triglycerides, and PNPLA3 risk variant predicted steatosis. CONCLUSIONS: Insulin resistance is the strongest predictor of liver fibrosis stage and hepatic inflammation in patients with alcohol-related liver disease. Genetic susceptibility further aggravates this risk. These data highlight the clinical value of detailed metabolic and genetic profiling of patients with excessive alcohol use.

A Protein-Truncating HSD17B13 Variant and Protection from Chronic Liver Disease.

BACKGROUND: Elucidation of the genetic factors underlying chronic liver disease may reveal new therapeutic targets. METHODS: We used exome sequence data and electronic health records from 46,544 participants in the DiscovEHR human genetics study to identify genetic variants associated with serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Variants that were replicated in three additional cohorts (12,527 persons) were evaluated for association with clinical diagnoses of chronic liver disease in DiscovEHR study participants and two independent cohorts (total of 37,173 persons) and with histopathological severity of liver disease in 2391 human liver samples. RESULTS: A splice variant (rs72613567:TA) in HSD17B13, encoding the hepatic lipid droplet protein hydroxysteroid 17-beta dehydrogenase 13, was associated with reduced levels of ALT (P=4.2×10-12) and AST (P=6.2×10-10). Among DiscovEHR study participants, this variant was associated with a reduced risk of alcoholic liver disease (by 42% [95% confidence interval {CI}, 20 to 58] among heterozygotes and by 53% [95% CI, 3 to 77] among homozygotes), nonalcoholic liver disease (by 17% [95% CI, 8 to 25] among heterozygotes and by 30% [95% CI, 13 to 43] among homozygotes), alcoholic cirrhosis (by 42% [95% CI, 14 to 61] among heterozygotes and by 73% [95% CI, 15 to 91] among homozygotes), and nonalcoholic cirrhosis (by 26% [95% CI, 7 to 40] among heterozygotes and by 49% [95% CI, 15 to 69] among homozygotes). Associations were confirmed in two independent cohorts. The rs72613567:TA variant was associated with a reduced risk of nonalcoholic steatohepatitis, but not steatosis, in human liver samples. The rs72613567:TA variant mitigated liver injury associated with the risk-increasing PNPLA3 p.I148M allele and resulted in an unstable and truncated protein with reduced enzymatic activity. CONCLUSIONS: A loss-of-function variant in HSD17B13 was associated with a reduced risk of chronic liver disease and of progression from steatosis to steatohepatitis. (Funded by Regeneron Pharmaceuticals and others.).

High Risk of Fatty Liver Disease Amplifies the Alanine Transaminase-Lowering Effect of a HSD17B13 Variant.

A common loss-of-function variant in HSD17B13 (rs72613567:TA) was recently found to protect from chronic liver disease. Whether the variant confers protection from specific risk factors for liver disease is unclear. We tested the association of rs72613567 with plasma levels of alanine transaminase (ALT) and clinical liver disease and mortality in 111,612 individuals from the Danish general population, including 497 with cirrhosis and 113 with hepatocellular carcinoma. HSD17B13 rs72613567:TA was associated with stepwise lower levels of plasma ALT of up to 1.3 U/L in TA/TA homozygotes versus T/T homozygotes. For each TA-allele, the risk of cirrhosis and hepatocellular carcinoma was reduced by 15% and 28%, respectively. In prospective analyses, the TA-allele was associated with up to 33% lower rates of liver-related mortality in the general population, and with up to 49% reduced liver-related mortality in patients with cirrhosis. The ALT-lowering effect of rs72613567:TA was amplified by increasing adiposity, alcohol consumption, and genetic risk of fatty liver disease. The TA-allele was associated with only marginally lower ALT in lean nondrinkers with low genetic risk of hepatic steatosis. In contrast, compared with T/T homozygotes, TA/TA homozygotes had 12% to 18% lower plasma ALT among the most obese, in heavy drinkers, and in individuals carrying three or four steatogenic alleles in patatin-like phospholipase domain-containing protein 3 (PNPLA3) and transmembrane 6 superfamily 2 (TM6SF2). Conclusion: High risk of fatty liver disease amplifies the ALT-lowering effect of HSD17B13 rs72613567:TA in the Danish general population.

Combined Effect of PNPLA3, TM6SF2, and HSD17B13 Variants on Risk of Cirrhosis and Hepatocellular Carcinoma in the General Population.

BACKGROUND AND AIMS: We hypothesized that a genetic risk score (GRS) for fatty liver disease influences the risk of cirrhosis and hepatocellular carcinoma (HCC). Three genetic variants (patatin-like phospholipase domain-containing protein 3 [PNPLA3] p.I148M; transmembrane 6, superfamily member 2 [TM6SF2] p.E167K; and hydroxysteroid 17-beta dehydrogenase 13 [HSD17B13] rs72613567) were combined into a risk score, ranging from 0 to 6 for risk-increasing alleles. APPROACH AND RESULTS: We examined the association of the risk score with plasma markers of liver disease and with cirrhosis and HCC in 110,761 individuals from Copenhagen, Denmark, and 334,691 individuals from the UK Biobank. The frequencies of risk scores of 0, 1, 2, 3, 4, and 5 or 6 were 5%, 25%, 41%, 23%, 5.5%, and 0.5%, respectively. A higher GRS was associated with an increase in plasma alanine aminotransferase (ALT) level of 26% in those with score 5 or 6 versus 0. In meta-analysis of the Copenhagen studies and the UK Biobank, individuals with scores 1, 2, 3, 4, and 5 or 6 had odds ratios (ORs) for cirrhosis of 1.6 (95% confidence interval [CI], 1.3, 1.9), 2.0 (95% CI, 1.8, 2.2), 3.1 (95% CI, 2.7, 3.5), 5.2 (95% CI, 4.2, 6.4), and 12 (95% CI, 7.7, 19), respectively, as compared with those with a score of 0. The corresponding ORs for HCC were 1.2 (95% CI, 0.9, 1.7), 1.0 (95% CI, 0.7, 1.3), 2.4 (95% CI, 1.9, 3.0), 3.3 (95% CI, 2.2, 5.0), and 29 (95% CI, 17, 51). CONCLUSION: A GRS for fatty liver disease confers up to a 12-fold higher risk of cirrhosis and up to a 29-fold higher risk of HCC in individuals from the general population.

Prevalence and Risk Factors of Moderate-to-Severe Hepatic Steatosis in Human Immunodeficiency Virus Infection: The Copenhagen Co-morbidity Liver Study.

BACKGROUND: People with human immunodeficiency virus (PWH) may be at risk of nonalcoholic fatty liver disease. We compared the prevalence of moderate-to-severe hepatic steatosis (M-HS) in PWH with human immunodeficiency virus (HIV)-uninfected controls and determined risk factors for M-HS in PWH. METHODS: The Copenhagen Co-Morbidity in HIV Infection study included 453 participants, and the Copenhagen General Population Study included 765 participants. None had prior or current viral hepatitis or excessive alcohol intake. Moderate-to-severe hepatic steatosis was assessed by unenhanced computed tomography liver scan defined by liver attenuation ≤48 Hounsfield units. Adjusted odds ratios (aORs) were computed by adjusted logistic regression. RESULTS: The prevalence of M-HS was lower in PWH compared with uninfected controls (8.6% vs 14.2%, P < .01). In multivariable analyses, HIV (aOR, 0.44; P < .01), female sex (aOR, 0.08; P = .03), physical activity level (aOR, 0.09; very active vs inactive; P < .01), and alcohol (aOR, 0.89 per unit/week; P = .02) were protective factors, whereas body mass index (BMI) (aOR, 1.58 per 1 kg/m2; P < .01), alanine transaminase (ALT) (aOR, 1.76 per 10 U/L; P < .01), and exposure to integrase inhibitors (aOR, 1.28 per year; P = .02) were associated with higher odds of M-HS. CONCLUSIONS: Moderate-to-severe hepatic steatosis is less common in PWH compared with demographically comparable uninfected controls. Besides BMI and ALT, integrase inhibitor exposure was associated with higher prevalence of steatosis in PWH.

Identification and Replication of Six Loci Associated With Gallstone Disease.

Gallstone disease is a common complex disease that confers a substantial economic burden on society. The genetic underpinnings of gallstone disease remain incompletely understood. We aimed to identify genetic associations with gallstone disease using publicly available data from the UK Biobank and two large Danish cohorts. We extracted genetic associations with gallstone disease from the Global Biobank Engine (GBE), an online browser of genome-wide associations in UK Biobank participants (14,940 cases and 322,268 controls). Significant associations (P < 5 × 10-8 ) were retested in two Copenhagen cohorts (comprising 1,522 cases and 18,266 controls). In the Copenhagen cohorts, we also tested whether a genetic risk score was associated with gallstone disease and whether individual gallstone loci were associated with plasma levels of lipids, lipoproteins, and liver enzymes. We identified 19 loci to be associated with gallstone disease in the GBE. Of these, 12 were replicated in the Copenhagen cohorts, including six previously unknown loci (in hepatocyte nuclear factor 4 alpha [HNF4A], fucosyltransferase 2, serpin family A member 1 [SERPINA1], jumonji domain containing 1C, AC074212.3, and solute carrier family 10A member 2 [SLC10A2]) and six known loci (in adenosine triphosphate binding cassette subfamily G member 8 [ABCG8], sulfotransferase family 2A member 1, cytochrome P450 7A1, transmembrane 4 L six family member 4, ABCB4, and tetratricopeptide repeat domain 39B). Five of the gallstone associations are protein-altering variants, and three (HNF4A p.Thr139Ile, SERPINA1 p.Glu366Lys, and SLC10A2 p.Pro290Ser) conferred per-allele odds ratios for gallstone disease of 1.30-1.36. Individuals with a genetic risk score >2.5 (prevalence 1%) had a 5-fold increased risk of gallstones compared to those with a score <1.0 (11%). Of the 19 lithogenic loci, 11 and ten exhibited distinct patterns of association with plasma levels of lipids and liver enzymes, respectively. Conclusion: We identified six susceptibility loci for gallstone disease.

Relationship between genetic variation at PPP1R3B and levels of liver glycogen and triglyceride.

Genetic variation at rs4240624 on chromosome 8 is associated with an attenuated signal on hepatic computerized tomography, which has been attributed to changes in hepatic fat. The closest coding gene to rs4240624, PPP1R3B, encodes a protein that promotes hepatic glycogen synthesis. Here, we performed studies to determine whether the x-ray attenuation associated with rs4240624 is due to differences in hepatic glycogen or hepatic triglyceride content (HTGC). A sequence variant in complete linkage disequilibrium with rs4240624, rs4841132, was genotyped in the Dallas Heart Study (DHS), the Dallas Liver Study, and the Copenhagen Cohort (n = 112,428) of whom 1,539 had nonviral liver disease. The minor A-allele of rs4841132 was associated with increased hepatic x-ray attenuation (n = 1,572; P = 4 × 10-5 ), but not with HTGC (n = 2,674; P = 0.58). Rs4841132-A was associated with modest, but significant, elevations in serum alanine aminotransferase (ALT) in the Copenhagen Cohort (P = 3 × 10-4 ) and the DHS (P = 0.004), and with odds ratios for liver disease of 1.13 (95% CI, 0.97-1.31) and 1.23 (1.01-1.51), respectively. Mice lacking protein phosphatase 1 regulatory subunit 3B (PPP1R3B) were deficient in hepatic glycogen, whereas HTGC was unchanged. Hepatic overexpression of PPP1R3B caused accumulation of hepatic glycogen and elevated plasma levels of ALT, but did not change HTGC. CONCLUSION: These observations are consistent with the notion that the minor allele of rs4841132 promotes a mild form of hepatic glycogenosis that is associated with hepatic injury. (Hepatology 2018;67:2182-2195).

Liver fat content, non-alcoholic fatty liver disease, and ischaemic heart disease: Mendelian randomization and meta-analysis of 279 013 individuals.

Aims: In observational studies, non-alcoholic fatty liver disease (NAFLD) is associated with high risk of ischaemic heart disease (IHD). We tested the hypothesis that a high liver fat content or a diagnosis of NAFLD is a causal risk factor for IHD. Methods and results: In a cohort study of the Danish general population (n = 94 708/IHD = 10 897), we first tested whether a high liver fat content or a diagnosis of NAFLD was associated observationally with IHD. Subsequently, using Mendelian randomization, we tested whether a genetic variant in the gene encoding the protein patatin-like phospholipase domain containing 3 protein (PNPLA3), I148M (rs738409), a strong and specific cause of high liver fat content and NAFLD, was causally associated with the risk of IHD. We found that the risk of IHD increased stepwise with increasing liver fat content (in quartiles) up to an odds ratio (OR) of 2.41 (1.28-4.51)(P-trend = 0.004). The corresponding OR for IHD in individuals with vs. without NAFLD was 1.65 (1.34-2.04)(P = 3×10-6). PNPLA3 I148M was associated with a stepwise increase in liver fat content of up to 28% in MM vs. II-homozygotes (P-trend = 0.0001) and with ORs of 2.03 (1.52-2.70) for NAFLD (P = 3×10-7), 3.28 (2.37-4.54) for cirrhosis (P = 4×10-12), and 0.95 (0.86-1.04) for IHD (P = 0.46). In agreement, in meta-analysis (N = 279 013/IHD = 71 698), the OR for IHD was 0.98 (0.96-1.00) per M-allele vs. I-allele. The OR for IHD per M-allele higher genetically determined liver fat content was 0.98 (0.94-1.03) vs. an observational estimate of 1.05 (1.02-1.09)(P for comparison = 0.02). Conclusion: Despite confirming the known observational association of liver fat content and NAFLD with IHD, lifelong, genetically high liver fat content was not causally associated with risk of IHD. These results suggest that the observational association is due to confounding or reverse causation.

Four Susceptibility Loci for Gallstone Disease Identified in a Meta-analysis of Genome-Wide Association Studies.

BACKGROUND & AIMS: A genome-wide association study (GWAS) of 280 cases identified the hepatic cholesterol transporter ABCG8 as a locus associated with risk for gallstone disease, but findings have not been reported from any other GWAS of this phenotype. We performed a large-scale, meta-analysis of GWASs of individuals of European ancestry with available prior genotype data, to identify additional genetic risk factors for gallstone disease. METHODS: We obtained per-allele odds ratio (OR) and standard error estimates using age- and sex-adjusted logistic regression models within each of the 10 discovery studies (8720 cases and 55,152 controls). We performed an inverse variance weighted, fixed-effects meta-analysis of study-specific estimates to identify single-nucleotide polymorphisms that were associated independently with gallstone disease. Associations were replicated in 6489 cases and 62,797 controls. RESULTS: We observed independent associations for 2 single-nucleotide polymorphisms at the ABCG8 locus: rs11887534 (OR, 1.69; 95% confidence interval [CI], 1.54-1.86; P = 2.44 × 10(-60)) and rs4245791 (OR, 1.27; P = 1.90 × 10(-34)). We also identified and/or replicated associations for rs9843304 in TM4SF4 (OR, 1.12; 95% CI, 1.08-1.16; P = 6.09 × 10(-11)), rs2547231 in SULT2A1 (encodes a sulfoconjugation enzyme that acts on hydroxysteroids and cholesterol-derived sterol bile acids) (OR, 1.17; 95% CI, 1.12-1.21; P = 2.24 × 10(-10)), rs1260326 in glucokinase regulatory protein (OR, 1.12; 95% CI, 1.07-1.17; P = 2.55 × 10(-10)), and rs6471717 near CYP7A1 (encodes an enzyme that catalyzes conversion of cholesterol to primary bile acids) (OR, 1.11; 95% CI, 1.08-1.15; P = 8.84 × 10(-9)). Among individuals of African American and Hispanic American ancestry, rs11887534 and rs4245791 were associated positively with gallstone disease risk, whereas the association for the rs1260326 variant was inverse. CONCLUSIONS: In this large-scale GWAS of gallstone disease, we identified 4 loci in genes that have putative functions in cholesterol metabolism and transport, and sulfonylation of bile acids or hydroxysteroids.

Using human genetics to predict the effects and side-effects of drugs.

PURPOSE OF REVIEW: 'Genetic proxies' are increasingly being used to predict the effects of drugs. We present an up-to-date overview of the use of human genetics to predict effects and adverse effects of lipid-targeting drugs. RECENT FINDINGS: LDL cholesterol lowering variants in HMG-Coenzyme A reductase and Niemann-Pick C1-like protein 1, the targets for statins and ezetimibe, protect against ischemic heart disease (IHD). However, HMG-Coenzyme A reductase and Niemann-Pick C1-Like Protein 1-variants also increase the risk of type 2 diabetes and gallstone disease, respectively. Mutations in proprotein convertase subtilisin kexin 9 (PCSK9), apolipoprotein B, and microsomal triglyceride transfer protein cause low LDL cholesterol and protect against IHD. In addition, mutations in apolipoprotein B and microsomal triglyceride transfer protein cause hepatic steatosis, in concordance with drugs that inhibit these targets. Both mutations in PCSK9 and PCSK9-inhibition seem without adverse effects. Mutations in APOC3 cause low triglycerides and protect against IHD, and recent pharmacological APOC3-inhibition reported major reductions in plasma triglycerides. Human genetics support that low lipoprotein(a) protects against IHD, without adverse effects, and the first trial of lipoprotein(a) inhibition reduced lipoprotein(a) up to 78%. SUMMARY: Recent genetic studies have confirmed the efficacy of statins and ezetimibe in protecting against IHD. Results from human genetics support that several lipid-lowering drugs currently under development are likely to prove efficacious in protecting against IHD, without major adverse effects.

HMG-coenzyme A reductase inhibition, type 2 diabetes, and bodyweight: evidence from genetic analysis and randomised trials.

BACKGROUND: Statins increase the risk of new-onset type 2 diabetes mellitus. We aimed to assess whether this increase in risk is a consequence of inhibition of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), the intended drug target. METHODS: We used single nucleotide polymorphisms in the HMGCR gene, rs17238484 (for the main analysis) and rs12916 (for a subsidiary analysis) as proxies for HMGCR inhibition by statins. We examined associations of these variants with plasma lipid, glucose, and insulin concentrations; bodyweight; waist circumference; and prevalent and incident type 2 diabetes. Study-specific effect estimates per copy of each LDL-lowering allele were pooled by meta-analysis. These findings were compared with a meta-analysis of new-onset type 2 diabetes and bodyweight change data from randomised trials of statin drugs. The effects of statins in each randomised trial were assessed using meta-analysis. FINDINGS: Data were available for up to 223 463 individuals from 43 genetic studies. Each additional rs17238484-G allele was associated with a mean 0·06 mmol/L (95% CI 0·05-0·07) lower LDL cholesterol and higher body weight (0·30 kg, 0·18-0·43), waist circumference (0·32 cm, 0·16-0·47), plasma insulin concentration (1·62%, 0·53-2·72), and plasma glucose concentration (0·23%, 0·02-0·44). The rs12916 SNP had similar effects on LDL cholesterol, bodyweight, and waist circumference. The rs17238484-G allele seemed to be associated with higher risk of type 2 diabetes (odds ratio [OR] per allele 1·02, 95% CI 1·00-1·05); the rs12916-T allele association was consistent (1·06, 1·03-1·09). In 129 170 individuals in randomised trials, statins lowered LDL cholesterol by 0·92 mmol/L (95% CI 0·18-1·67) at 1-year of follow-up, increased bodyweight by 0·24 kg (95% CI 0·10-0·38 in all trials; 0·33 kg, 95% CI 0·24-0·42 in placebo or standard care controlled trials and -0·15 kg, 95% CI -0·39 to 0·08 in intensive-dose vs moderate-dose trials) at a mean of 4·2 years (range 1·9-6·7) of follow-up, and increased the odds of new-onset type 2 diabetes (OR 1·12, 95% CI 1·06-1·18 in all trials; 1·11, 95% CI 1·03-1·20 in placebo or standard care controlled trials and 1·12, 95% CI 1·04-1·22 in intensive-dose vs moderate dose trials). INTERPRETATION: The increased risk of type 2 diabetes noted with statins is at least partially explained by HMGCR inhibition. FUNDING: The funding sources are cited at the end of the paper.

Genetic variation in the cholesterol transporter NPC1L1, ischaemic vascular disease, and gallstone disease.

AIMS: Ezetimibe reduces plasma levels of low-density lipoprotein (LDL) cholesterol by inhibiting Niemann-Pick C1-Like protein 1 (NPC1L1), the transporter responsible for cholesterol uptake from the intestine into enterocytes and from the bile into hepatocytes. We tested the hypothesis that genetic variation in NPC1L1, mimicking the effect of ezetimibe, was associated with reduced risk of ischaemic vascular disease (IVD) and with increased risk of symptomatic gallstone disease. METHODS AND RESULTS: We included 67 385 individuals from the general population. Of these, 5255 and 3886 individuals developed IVD or symptomatic gallstone disease, respectively, during follow-up from 1977 to 2013. We genotyped four common NPC1L1 variants, previously associated with reduced LDL cholesterol levels, thus mimicking the effect of ezetimibe, and calculated a weighted genotype score. With increasing genotype score, LDL cholesterol decreased stepwise up to 3.5% (0.12 mmol/L) and total cholesterol up to 1.9% (0.11 mmol/L) (P-trend: 2 × 10(-12) and 2 × 10(-9)). The cumulative incidence by age of IVD decreased, while that of symptomatic gallstone disease increased as a function of increasing genotype score (P-trend: 0.005 and 0.01). Hazard ratios for genotype scores ≥ 5.0 vs. <2.0 were 0.82 (95% confidence interval: 0.70-0.95) for IVD and 1.22 (0.99-1.49) for gallstone disease (P-trend across genotype scores: 0.004 and 0.01). CONCLUSION: Genetic variation in NPC1L1 is associated with a reduction in risk of IVD, with a corresponding reduction in LDL cholesterol, but with a concomitant increased risk of gallstone disease. These data support the hypothesis that treatment with ezetimibe protects against IVD but raise the question whether long-term treatment increases the risk of gallstone disease.

Adult-onset liver disease and hepatocellular carcinoma in S-adenosylhomocysteine hydrolase deficiency.

BACKGROUND: The etiology of liver disease remains elusive in some adults presenting with severe hepatic dysfunction. METHODS AND RESULTS: Here we describe a woman of Pakistani descent who had elevated aminotransferases at age 23. She developed muscle weakness in her mid-20s, and was diagnosed with hepatocellular carcinoma at age 29. She died without a diagnosis at age 32 after having a liver transplant. Exome sequencing revealed that she was homozygous for a missense mutation (R49H) in AHCY, the gene encoding S-adenosylhomocysteine (SAH) hydrolase. SAH hydrolase catalyzes the final step in conversion of methionine to homocysteine and inactivating mutations in this enzyme cause a rare autosomal recessive disorder, SAH hydrolase deficiency, that typically presents in infancy. An asymptomatic 7-year old son of the proband is also homozygous for the AHCY-R49H mutation and has elevated serum aminotransferase levels, as well as markedly elevated serum levels of SAH, S-adenosylmethionine (SAM), and methionine, which are hallmarks of SAH hydrolase deficiency. CONCLUSION: This report reveals several new aspects of SAH hydrolase deficiency. Affected women with SAH hydrolase deficiency can give birth to healthy children. SAH hydrolase deficiency can remain asymptomatic in childhood, and the disorder can be associated with early onset hepatocellular carcinoma. The measurement of serum amino acids should be considered in patients with liver disease or hepatocellular carcinoma of unknown etiology.