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Background Genetic factors influence the risk of fatty liver disease (FLD) in adults. The aim of this study was to test if, and when, genetic risk factors known to affect FLD in adults begin to exert their deleterious effects during childhood, adolescence and early adulthood. Methods We included up to 4018 British children and adolescents from the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort. Three genetic variants known to associate robustly with FLD in adults (PNPLA3 rs738409, TM6SF2 rs58542926 and HSD17B13 rs72613567) were tested for association with plasma levels of alanine transaminase (ALT) and aspartate transaminase (AST) during childhood (mean age: 9.9 years), early adolescence (15.5 years), late adolescence (17.8 years), and early adulthood (24.5 years). We also tested the associations of a 17-variant score and whole-genome polygenic risk scores (PRS) derived from associations in adults with plasma ALT and AST at the same four time points. Associations with elastography-derived liver steatosis and fibrosis were tested in early adulthood. Results Genetic risk factors for FLD (individually, combined into a 3-variant score, a 17-variant score and as a genome-wide PRS), were associated with higher liver enzymes, beginning in childhood and throughout adolescence and early adulthood. The ALT-increasing effects of the genetic risk variants became larger with increasing age. The ALT-PRS was associated with liver steatosis in early adulthood. No genetic associations with fibrosis were observed. Conclusions Genetic factors that promote FLD in adults associate with elevated liver enzymes already during childhood, and their effects get amplified with increasing age.

Background: A genetic variant in the manganese transporter SLC30A10 (rs188273166, p.Thr95Ile) was associated with increased plasma alanine transaminase (ALT) in a recent genome-wide association study in the UK Biobank (UKB). The aims of the present study were to test the association of rs188273166 with ALT in an independent cohort, and to begin to assess the clinical, hepatic, and biochemical phenotypes associated with the variant. Methods: We included n = 334,886 white participants from UKB, including 14,462 with hepatic magnetic resonance imaging (MRI), and n = 113,612 individuals from the Copenhagen City Heart Study and the Copenhagen General Population Study combined. Results: Genotyping SLC30A10 p.Thr95Ile identified 816 heterozygotes in the UKB and 111 heterozygotes in the Copenhagen cohort. Compared to noncarriers, heterozygotes had 4 and 5 U/L higher levels of ALT in the UKB and Copenhagen cohort, respectively, and 3 U/L higher plasma aspartate transaminase and gamma-glutamyl transferase in the UKB. Heterozygotes also had higher corrected T1 on liver MRI, a marker of hepatic inflammation (p = 4 × 10–7), but no change in MRI-quantified steatosis (p = 0.57). Plasma manganese was within the normal range in nine heterozygotes that provided new blood samples. SLC30A10 p.Thr95Ile heterozygotes had an eightfold increased risk of biliary tract cancer in UKB (p = 4 × 10–7), but this association was not replicated in the Copenhagen cohort. Conclusions: SLC30A10 p.Thr95Ile was associated with elevated liver enzymes in two large general population cohorts, and with MRI-quantified hepatic inflammation. Graphical abstract: A rare genetic variant (p.Thr95Ile) in the manganese transporter SLC30A10 is associated with elevated plasma alanine transaminase (ALT) and higher corrected T1 on liver MRI, markers of liver inflammation. These data support that the variant may increase the risk of liver disease. [Figure not available: see fulltext.]

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 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.

Glaucoma is a leading cause of blindness. Current glaucoma medications work by lowering intraocular pressure (IOP), a risk factor for glaucoma, but most treatments do not directly target the pathological changes leading to increased IOP, which can manifest as medication resistance as disease progresses. To identify physiological modulators of IOP, we performed genome- and exome-wide association analysis in >129,000 individuals with IOP measurements and extended these findings to an analysis of glaucoma risk. We report the identification and functional characterization of rare coding variants (including loss-of-function variants) in ANGPTL7 associated with reduction in IOP and glaucoma protection. We validated the human genetics findings in mice by establishing that Angptl7 knockout mice have lower (~2 mmHg) basal IOP compared to wild-type, with a trend towards lower IOP also in heterozygotes. Conversely, increasing mAngptl7 levels via injection into mouse eyes increases the IOP. We also show that acute gene silencing via siRNA knockdown of Angptl7 in adult mice lowers the IOP (~2-4 mmHg), reproducing the observations in knockout mice. Collectively, our data suggest that ANGPTL7 is important for IOP homeostasis and is amenable to therapeutic modulation to help maintain a healthy IOP that can prevent onset or slow the progression of glaucoma.

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 2.5 (prevalence 1%) had a 5-fold increased risk of gallstones compared to those with a score

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

Background Elevated plasma concentrations of liver enzymes are routinely used as markers of liver injury in adults and children. Currently, the age- and sex-specific effects of adiposity on pediatric liver enzyme concentrations are unclear. Methods We included participants from 2 cohorts of Danish children and adolescents: 1858 from a population-based cohort and 2155 with overweight or obesity, aged from 6 to 18 years. Age- and sex-specific percentile curves were calculated for fasting plasma concentrations of alanine transaminase (ALT), aspartate transaminase (AST), lactate dehydrogenase (LDH), gamma-glutamyltransferase (GGT), bilirubin, and alkaline phosphatase (ALP) in both cohorts. Hepatic fat content was assessed by proton magnetic resonance spectroscopy in 458 participants. Results Concentrations of ALT, AST, LDH, and ALP decreased with age in both girls and boys, while GGT and bilirubin were comparable across age groups in girls and increased slightly with age in boys. Children and adolescents with overweight or obesity exhibited higher concentrations of ALT in all age groups. Concentrations of ALT, and to a lesser degree GGT, increased with age in boys with overweight or obesity. Optimal ALT cut-points for diagnosing hepatic steatosis (liver fat content > 5%) was 24.5 U/L for girls (sensitivity: 55.6%, specificity: 84.0%), and 34.5 U/L for boys (sensitivity: 83.7%, specificity: 68.2%). Conclusions Pediatric normal values of liver enzymes vary with both age and sex. Overweight and obesity is associated with elevated biochemical markers of liver damage. These findings emphasize the need for prevention and treatment of overweight and obesity in children and adolescents. (J Clin Endocrinol Metab XX: 0-0, 2019)

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.

Context A common genetic variant near PPP1R3B (rs4841132G > A) has been associated with increased hepatic computed tomography (CT) attenuation and with plasma levels of glucose and liver enzymes. Objective To elucidate the association of rs4841132 with hepatic CT attenuation, and to test if synergistic effects modify the association of the variant with plasma glucose and liver enzymes. Design Population-based cohort study. Setting and Participants The Copenhagen City Heart Study and the Copenhagen General Population Study combined, totaling 107 192 individuals from the Danish general population. Hepatic CT scans were available in 6445 individuals. Main Outcome Measures Hepatic CT attenuation and plasma levels of glucose and liver enzymes. Results The rs4841132 A-allele (rs4841132-A) was associated with higher hepatic CT attenuation (P = 5 × 10−6). The probability of carrying rs4841132-A increased with higher hepatic CT attenuation in the range above 65 Hounsfield units, but remained constant at the range below (P = 4 × 10−8 for nonlinearity). Rs4841132-A was associated with up to 0.17 mmol/L higher plasma glucose in fasting individuals, but with up to 0.17 mmol/L lower glucose in postprandial individuals (P = 6 × 10−5 for interaction between rs4841132 and time since last meal on plasma glucose). Finally, rs4841132-A was associated with up to 2 U/L higher plasma alanine transaminase (P = 3 × 10−6). This association was not modified by adiposity, alcohol intake, or steatogenic genetic risk. Conclusions Rs4841132-A associates with higher hepatic CT attenuation in a distinctly nonlinear manner, and its association with plasma glucose depends on prandial status. The overall association pattern supports that rs4841132-A promotes hepatic glycogen synthesis postprandially.

Background & AimsA common genetic variant near MBOAT7 (rs641738C>T) has been previously associated with hepatic fat and advanced histology in non-alcoholic fatty liver disease (NAFLD), however, these findings have not been consistently replicated in the literature. We aimed to establish whether rs641738C>T is a risk factor across the spectrum of NAFLD and characterize its role in the regulation of related metabolic phenotypes through meta-analysis.MethodsWe performed meta-analysis of studies with data on the association between rs641738C>T genotype and: liver fat, NAFLD histology, and serum ALT, lipids, or insulin. These included directly genotyped studies and population-level data from genome-wide association studies (GWAS). We performed random effects meta-analysis using recessive, additive, and dominant genetic models.ResultsData from 1,047,265 participants (8,303 with liver biopsies) across 42 studies was included in the meta-analysis. rs641738C>T was associated with higher liver fat on CT/MRI (+0.03 standard deviations [95% CI: 0.02 - 0.05]) and diagnosis of NAFLD (OR 1.22 [95% CI 1.08 - 1.39]) in Caucasian adults. The variant was also positively associated with presence of severe steatosis, NASH, and advanced fibrosis (OR: 1.32 [95% CI: 1.06 - 1.63]) in Caucasian adults using a recessive model of inheritance (CC+CT vs. TT). Meta-analysis of data from previous GWAS found the variant to be associated with higher ALT (Pz=0.002) and lower serum triglycerides (Pz=1.5×10−4). rs641738C>T was not associated with fasting insulin and no effect was observed in children with NAFLD.ConclusionOur study validates rs641738C>T near MBOAT7 as a risk factor for the presence and severity of NAFLD in individuals of European descent.

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.

Background Results from randomized controlled trials (RCTs) have raised concern that the cholesterol-lowering drug ezetimibe might increase the risk of cancer. We tested the hypothesis that genetic variation in NPC1L1, mimicking treatment with ezetimibe, was associated with an increased risk of cancer. Methods We included 67 257 individuals from the general population. Of these, 8333 developed cancer and 2057 died of cancer from 1968 to 2011. To mimic the effect of ezetimibe, we calculated weighted allele scores based on the low-density lipoprotein (LDL) cholesterol-lowering(= NPC1L1-inhibitory) effect of each variant. We tested the associations of the NPC1L1 allele scores with LDL cholesterol and with risk of any cancer, death from any cancer and 27 site-specific cancers. As a positive control, we tested the association of the NPC1L1 allele scores with risk of ischaemic vascular disease (IVD). Results The NPC1L1 allele scores did not associate with risk of any cancer, death from any cancer or with any of 27 site-specific cancers. Hazard ratios (HRs) for a 1-unit increase in internally weighted allele scores were 1.00 (95% confidence interval: 0.98-1.02) for any cancer, and 1.02 (0.98-1.06) for cancer death. The corresponding HR for IVD was 0.97 (0.94-0.99). Results were similar for an externally weighted allele score and for a simple allele count. Finally, the null association with cancer was robust in sensitivity analyses. Conclusions Lifelong, genetic inhibition of NPC1L1, mimicking treatment with ezetimibe, does not associate with risk of cancer. These results suggest that long-term treatment with ezetimibe is unlikely to increase the risk of cancer, in agreement with the overall evidence from ezetimibe RCTs.

Jonathan Cohen, Helen Hobbs and colleagues show that adiposity significantly amplifies the effects of PNPLA3, TM6SF2, and GCKR sequence variants on nonalcoholic fatty liver disease. They find that synergy between adiposity and genotype influences the full spectrum of the disease, from steatosis to hepatic inflammation and cirrhosis. Complex traits arise from the interplay between genetic and environmental factors. The actions of these factors usually appear to be additive, and few compelling examples of gene–environment synergy have been documented. Here we show that adiposity significantly amplifies the effect of three sequence variants (encoding PNPLA3 p.I148M, TM6SF2 p.E167K, and GCKR p.P446L) associated with nonalcoholic fatty liver disease (NAFLD). Synergy between adiposity and genotype promoted the full spectrum of NAFLD, from steatosis to hepatic inflammation to cirrhosis. We found no evidence of strong interaction between adiposity and sequence variants influencing other adiposity-associated traits. These results indicate that adiposity augments genetic risk of NAFLD at multiple loci that confer susceptibility to hepatic steatosis through diverse metabolic mechanisms.

Coffee intake is associated with low risk of symptomatic gallstone disease (GSD). We tested the hypothesis that high coffee intake causally protects against symptomatic GSD using a Mendelian randomization design.First, we tested whether high coffee intake was associated with low risk of GSD in 104 493 individuals from the general population. Mean follow-up was 8 years (range: 1-13 years). Secondly, we tested whether two genetic variants near CYP1A1/A2 (rs2472297) and AHR (rs4410790), combined as an allele score, were associated with higher coffee intake measured as a continuous variable. Thirdly, we tested whether the allele score was associated with lower risk of GSD in 114 220 individuals including 7294 gallstone events. Mean follow-up was 38 years (range:1-40 years).In observational analysis, those with coffee intake of6 cups daily had 23% lower risk of GSD compared to individuals without coffee intake [hazard ratio (HR) = 0.77 (95% confidence interval: 0.61-0.94)]. In genetic analysis, there was a stepwise higher coffee intake of up to 41% (caffeine per day) in individuals with 4 (highest) versus 0 (lowest) coffee intake alleles (P for trend = 3 x 10High coffee intake is associated observationally with low risk of GSD, and with genetic evidence to support a causal relationship.

Heart failure (HF) is a leading cause of morbidity and mortality worldwide1. A small proportion of HF cases are attributable to monogenic cardiomyopathies and existing genome-wide association studies (GWAS) have yielded only limited insights, leaving the observed heritability of HF largely unexplained2–4. We report the largest GWAS meta-analysis of HF to-date, comprising 47,309 cases and 930,014 controls. We identify 12 independent variant associations with HF at 11 genomic loci, all of which demonstrate one or more associations with coronary artery disease (CAD), atrial fibrillation, or reduced left ventricular function suggesting shared genetic aetiology. Expression quantitative trait analysis of non-CAD-associated loci implicate genes involved in cardiac development (MYOZ1, SYNPO2L), protein homeostasis (BAG3), and cellular senescence (CDKN1A). Using Mendelian randomisation analysis we provide new evidence supporting previously equivocal causal roles for several HF risk factors identified in observational studies, and demonstrate CAD-independent effects for atrial fibrillation, body mass index, hypertension and triglycerides. These findings extend our knowledge of the genes and pathways underlying HF and may inform the development of new therapeutic approaches.

Carbon‐13 magnetic resonance spectroscopy (MRS) following oral intake of 13C‐labeled glucose is the gold standard for imaging glycogen metabolism in humans. However, the temporal resolution of previous studies has been >13 minutes. Here, we describe a high‐sensitivity 13C MRS method for imaging hepatic glycogen synthesis with a temporal resolution of 1 minute or less. Nuclear magnetic resonance spectra were acquired from the liver of 3 healthy volunteers, using a 13C clamshell radiofrequency transmit and paddle‐shaped array receive coils in a 3 Tesla magnetic resonance imaging system. Following a 15‐minute baseline 13C MRS scan of the liver, [1‐13C]‐glucose was ingested and 13C MRS data were acquired for an additional 1‐3 hours. Dynamic change of the hepatic glycogen synthesis level was analyzed by reconstructing the acquired MRS data with temporal resolutions of 30 seconds to 15 minutes. Plasma levels of 13C‐labeled glucose and lactate were measured using gas chromatography–mass spectrometry. While not detected at baseline 13C MRS, [1‐13C]‐labeled α‐glucose and β‐glucose and glycogen peaks accumulated rapidly, beginning as early as ~2 minutes after oral administration of [1‐13C]‐glucose. The [1‐13C]‐glucose signals peaked at ~5 minutes, whereas [1‐13C]‐glycogen peaked at ~25 minutes after [1‐13C]‐glucose ingestion; both signals declined toward baseline levels over the next 1‐3 hours. Plasma levels of 13C‐glucose and 13C‐lactate rose gradually, and approximately 20% of all plasma glucose and 5% of plasma lactate were 13C‐labeled by 2 hours after ingestion. Conclusion: We observed rapid accumulation of hepatic [1‐13C]‐glycogen following orally administered [1‐13C]‐glucose, using a dynamic 13C MRS method with a temporal resolution of 1 minute or less. Commercially available technology allows high temporal resolution studies of glycogen metabolism in the human liver., In this study, we describe a high‐sensitivity 13C MRS method for imaging hepatic glycogen synthesis with improved temporal resolution. We observed rapid accumulation of hepatic [1‐13C]‐glycogen following orally administered [1‐13C]‐glucose, using a dynamic 13C MRS method with a temporal resolution of 1 minute or less.

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.

'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.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%.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.

Non-alcoholic fatty liver disease (NAFLD) is a buildup of excessive fat in the liver that can lead to liver damage resembling the damage caused by alcohol abuse, but that occurs in people who do not drink heavily. The disease is of complex and of multifactorial origin. Insulin resistance and obesity are considered major risk factors for the development and progression of NAFLD, however, an important genetic component has been demonstrated. Recent phenotypic characterization of a large number of individuals with NAFLD and developments in genotyping technology has allowed for identification of common genetic variants associating with NAFLD. This book chapter focuses on recent insights into the genetics of NAFLD and directions for future genetic studies are discussed.

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 found to be associated with reduced levels of ALT (P=4.20×10(−12)) and AST (P=6.2×10(−10)). Among DiscovEHR study participants, this variant was found to be 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 is associated with a reduced risk of chronic liver disease and of progression from steatosis to steatohepatitis. (Funded by Regeneron Pharmaceuticals and others.)

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.

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).

ObjectivesThe study sought to test the hypothesis that genetic variation in ABCG5/8, the transporter responsible for intestinal and hepatobiliary cholesterol efflux, may simultaneously influence plasma and biliary cholesterol levels, and hence risk of myocardial infarction (MI) and gallstone disease in opposite directions.BackgroundHigh plasma levels of low-density lipoprotein (LDL) cholesterol are a causal risk factor for MI, whereas high levels of biliary cholesterol promote gallstone formation.MethodsA total of 60,239 subjects from Copenhagen were included, including 5,647 with MI and 3,174 with symptomatic gallstone disease. Subjects were genotyped for 6 common, nonsynonymous and functional variants in ABCG5/8, and a combined weighted genotype score was calculated.ResultsCombined, weighted genotype scores were associated with stepwise decreases in LDL cholesterol of up to 5.9% (0.20 mmol/l) for individuals with a score ≥8.0 (prevalence = 11%) versus

HSD17B13, Chronic Liver Disease, and Ancestry The established association between variant HSD17B13 and protection against chronic liver disease has been replicated. A newly discovered, probably dam...

Elevated body mass index (BMI) is associated with an increased risk of gallstone disease. Whether this reflects a causal association is unknown. Using a Mendelian randomization approach, we studied 77,679 individuals from the general population. Of these, 4,106 developed symptomatic gallstone disease during up to 34 years of follow-up. Subjects were genotyped for three common variants known to associate with BMI: FTO(rs9939609); MC4R(rs17782313); and TMEM18(rs6548238). The number of BMI-increasing alleles was calculated for each participant. In observational analyses, mean baseline BMI was 55% (11.6 kg/m2) increased in individuals in the fifth quintile versus the first quintile, similar in women and men. The corresponding multifactorially adjusted hazard ratio (HR) for symptomatic gallstone disease was 2.84 (95% confidence interval [CI]: 2.32-3.46) overall, 3.36 (95% CI: 2.62-4.31) in women, and 1.51 (95% CI: 1.09-2.11) in men (P trend: 0.001 to

Drugs which reduce plasma low-density lipoprotein cholesterol (LDL-C) may protect against gallstone disease. Whether plasma levels of LDL-C per se predict risk of gallstone disease remains unclear. We tested the hypothesis that elevated LDL-C is a causal risk factor for symptomatic gallstone disease.We used a Mendelian randomization approach and genotyped 63,051 individuals from a prospective cohort study of the general Danish population, including 3323 subjects with symptomatic gallstones. We selected eight genetic variants in APOE, APOB, LDLR, and PCSK9 affecting LDL-C. Furthermore, studies of APOE rs429358/rs7412 (defining ε2/ε3/ε4 alleles; 12 studies) and APOB rs693 (eight studies) were included in meta-analyses.The observational hazard ratio (HR) for symptomatic gallstone disease for the fifth versus first quintile of LDL-C was 0.94 (95% confidence interval: 0.76-1.17), despite a corresponding 134% increase in LDL-C. Furthermore, although individual genetic variants in APOE, APOB, LDLR, and PCSK9 associated with stepwise increases/decreases in LDL-C of up to +59% compared with non-carriers (p0.001), none predicted the risk of symptomatic gallstone disease. Combining all variants into 10 genotypes, carriers of 9 versus ⩽3 LDL-C increasing alleles associated with 41% increased LDL-C (p0.001), but predicted a HR for symptomatic gallstone disease of 1.09 (0.70-1.69). Finally, in meta-analyses, random effects odds ratios for gallstone disease were 0.91 (0.78-1.06) for carriers of APOE ε4 versus non-carriers, and 1.25 (0.95-1.63) for APOB rs693 CT+TT versus CC.Results from the observational study, genetic studies, and meta-analyses suggest that elevated plasma levels of LDL-C are not causally associated with increased risk of symptomatic gallstone disease.

Background Elevated plasma levels of bilirubin, an endogenous antioxidant, have been associated with reduced risk of ischaemic heart disease (IHD) and myocardial infarction (MI). Whether this is a causal relationship remains unclear. Objective We tested the hypothesis that elevated plasma bilirubin is causally related to decreased risk of IHD and MI. Design We used a Mendelian randomization approach and three independent studies from Copenhagen, Denmark. We measured bilirubin in 43 708 white individuals from the general population, and genotyped rs6742078 G>T in the uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) gene in 67 068 individuals, of whom 11 686 had IHD. Results Third versus first tertile of baseline bilirubin levels was associated with 134% increased bilirubin levels, with sex- and age-adjusted hazard ratios (HRs) of 0.86 [95% confidence interval (CI), 0.76–0.98; P = 0.02] for IHD and 0.81 (95% CI, 0.66–0.99; P = 0.04) for MI, but with corresponding multifactorially adjusted HRs of 0.93 (95% CI, 0.82–1.06; P = 0.29) and 0.90 (95% CI, 0.73–1.12; P = 0.35). UGT1A1 rs6742078 TT versus GG genotype was associated with 95% increased bilirubin levels (P

Background Low plasma levels of low-density lipoprotein (LDL) cholesterol are associated with an increased risk of cancer, but whether this association is causal is unclear. Methods We studied 10 613 participants in the Copenhagen City Heart Study (CCHS) and 59 566 participants in the Copenhagen General Population Study, 6816 of whom had developed cancer by May 2009. Individuals were genotyped for PCSK9 R46L (rs11591147), ABCG8 D19H (rs11887534), and APOE R112C (rs429358) and R158C (rs7412) polymorphisms, all of which are associated with lifelong reduced plasma LDL cholesterol levels. Plasma LDL cholesterol was calculated using the Friedewald equation in samples in which the triglyceride level was less than 354 mg/dL and measured directly by colorimetry for samples with higher triglyceride levels. Risk of cancer was estimated prospectively using Cox proportional hazards regression analyses and cross-sectionally by logistic regression analyses. Causality was studied using instrumental variable analysis. All statistical tests were two-sided. Results In the CCHS, compared with plasma LDL cholesterol levels greater than the 66th percentile (>158 mg/dL), those lower than the 10th percentile (

Two new studies report that triglyceride (TG)-lowering mutations in APOC3 reduce coronary heart disease (CHD) (Crosby et al., 2014; Jørgensen et al., 2014). Here, we explore limitations of using Mendelian randomization to evaluate CHD risk, including potential confounding by the widespread use of statin therapy.

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.

We read with great interest the recent paper by Ference et al. [(1)][1] using genetic variants in NPC1L1 (target for ezetimibe) and HMGCR (target for statins) to predict the effect of ezetimibe and statins on low-density lipoprotein (LDL) cholesterol and risk of coronary heart disease. Ezetimibe

Background:A high dietary protein (P) content and low glycemic index (GI) have been suggested to be beneficial for weight management, but long-term studies are scarce.Objective:The DIOGENES randomized clinical trial investigated the effect of P and GI on weight loss maintenance in overweight or obese adults in 8 centers across Europe. This study reports the 1-year results in 2 of the centers that extended the intervention to 1 year.Method:After an 8-week low calorie diet (LCD), 256 adults (BMI>27 kg/m2) were randomized to 5 ad libitum diets for 12 months: high P/low GI (HP/LGI), high P/high GI (HP/HGI), low P/low GI (LP/LGI), low P/high GI (LP/HGI) and a control diet. During the first 6 months foods were provided for free through a shop system, during the whole 12-month period subjects received guidance by a dietician. Primary outcome variable was the change in body weight over the 12-month intervention period.Results:During the LCD period subjects lost 11.2 (10.8, 12.0) kg (mean (95% CI)). Average weight regain over the 12-month intervention period was 3.9 (95% CI 3.0 to 4.8) kg. Subjects on the HP diets regained less weight than subjects on the LP diets. The difference in weight regain after 1 year was 2.0 (0.4, 3.6) kg (P=0.017) (completers analysis, N=139) or 2.8 (1.4, 4.1) kg (P

In individuals without blockage of their bile ducts, levels of plasma bilirubin likely reflect levels of biliary bilirubin; higher biliary bilirubin levels may increase the risk of gallstone disease.To test the hypothesis that a lifelong increase in plasma bilirubin levels is a causal risk factor for symptomatic gallstone disease in the general population.In a prospective study of the Danish general population (N = 61,212), we first tested whether elevated levels of plasma bilirubin predicted greater risk of symptomatic gallstone disease. Second, taking advantage of mendelian randomization, we tested whether a genetic variant in the bilirubin glucoronidating enzyme UGT1A1 (rs6742078) was associated with increased plasma bilirubin levels and, in turn, with an increased risk of symptomatic gallstone disease.Plasma bilirubin level and symptomatic gallstone disease.During 34 years of follow-up, 3374 individuals developed symptomatic gallstone disease. In adjusted analyses, persons with plasma bilirubin levels in the 10th decile had a greater risk of symptomatic gallstone disease compared with those with plasma bilirubin levels in deciles 1 through 9; the hazard ratios (HRs) (95% CIs) were 1.57 (1.26-1.96) overall, 1.36 (1.02-1.82) in women, and 2.00 (1.41-2.83) in men. UGT1A1 genotype explained 20% of the total variation in plasma bilirubin levels and was associated with increases in the mean plasma bilirubin level overall of +16% (+0.09 mg/dL) in GT heterozygotes and +90% (+0.50 mg/dL) in TT homozygotes compared with GG homozygotes, with similar effects in women and men (P for trend.001 for all). The corresponding HRs (95% CIs) for symptomatic gallstone disease were 1.09 (1.02-1.17) for GT heterozygotes and 1.22 (1.09-1.36) for TT homozygotes vs GG homozygotes and similar in women and men (P for trend = .04-.001).These results are compatible with a causal association between extreme levels of plasma bilirubin and increased risk of symptomatic gallstone disease.

The aim was to compare the effect on atherogenesis of dietary monounsaturated and saturated fatty acids in cholesterol-clamped rabbits. To obtain an average plasma cholesterol concentration of 20 mmol/l in each rabbit during the 13-week cholesterol-feeding period, dietary cholesterol was adjusted weekly. The amount of fat fed daily was 10 g per rabbit in Expts A (n23), C (n36), and D (n58) and 5 g per rabbit in Expt B (n24). The source of monounsaturated fatty acids was olive oil in all four experiments. The source of saturated fatty acids was butter in Expt A, lard in Expt B, coconut oil in Expt C, and butter or lard in Expt D. Generally, olive oil-fed groups received more cholesterol and tended to have more cholesterol in VLDL and less in LDL compared with groups receiving saturated fat. Analysis of variance of the combined results of all four experiments showed that, in comparison with saturated fat, olive oil lowered aortic cholesterol by 13 (−9–30, 95% confidence interval) % in the aortic arch, and by 10 (−10–26) % in the thoracic aorta, which was not significant. In the comparison with olive oil, no differences in effects on aortic cholesterol content were detected between butter, lard and coconut oil. These findings do not support the view that replacement of dietary saturated fat with olive oil has a major impact on the development of atherosclerosis in addition to that accounted for by changes in plasma cholesterol levels.