Technological readiness and implementation of genomic-driven precision medicine for complex diseases.

The fields of human genetics and genomics have generated considerable knowledge about the mechanistic basis of many diseases. Genomic approaches to diagnosis, prognostication, prevention and treatment - genomic-driven precision medicine (GDPM) - may help optimize medical practice. Here, we provide a comprehensive review of GDPM of complex diseases across major medical specialties. We focus on technological readiness: how rapidly a test can be implemented into health care. Although these areas of medicine are diverse, key similarities exist across almost all areas. Many medical areas have, within their standards of care, at least one GDPM test for a genetic variant of strong effect that aids the identification/diagnosis of a more homogeneous subset within a larger disease group or identifies a subset with different therapeutic requirements. However, for almost all complex diseases, the majority of patients do not carry established single-gene mutations with large effects. Thus, research is underway that seeks to determine the polygenic basis of many complex diseases. Nevertheless, most complex diseases are caused by the interplay of genetic, behavioural and environmental risk factors, which will likely necessitate models for prediction and diagnosis that incorporate genetic and non-genetic data.

Estimated salt intake and risk of atrial fibrillation in a prospective community-based cohort.

INTRODUCTION: Hypertension predisposes to atrial fibrillation (AF) - a major risk factor for ischaemic stroke. Since a high dietary salt consumption is associated with hypertension, we investigated the association between urinary sodium excretion as a marker for dietary sodium intake and risk of new-onset AF in community-dwelling adults. METHOD: The UK Biobank includes 40- to 69-year-old British residents recruited 2006-2010. Participants were divided into sex-specific quintiles according to 24-hour sodium excretion estimated based on spot samples with the Kawasaki equation. We excluded participants with AF at baseline. Cox regression adjusted for cardiovascular risk factors was used to assess associations with risk of AF, using the third quintile as reference. RESULTS: A total of 257 545 women and 215 535 men were included. During up to 10 years' follow-up, 2221 women and 3751 men were diagnosed with AF. There was a tendency for an increased risk of AF in the lowest and highest quintiles of estimated daily salt intake in both women and men. In the fully adjusted model, significant associations were seen amongst men in the lowest and highest quintiles of sodium excretion (hazard ratio, HRQv1 , 1.20; 95% CI, 1.08-1.32, P < 0.001, and HRQv5 1.15, 95% CI, 1.03-1.27, P = 0.011). CONCLUSION: We found evidence for a U-shaped association between estimated daily salt intake and AF risk amongst men. A suggestive J-shaped association in women was not statistically confirmed, but analyses were likely underpowered. Our results suggest that above a certain physiological minimum level progressively higher salt intake is associated with increasing risk of AF.

Periodontal disease is associated with carotid plaque area: the Malmö Offspring Dental Study (MODS).

BACKGROUND: Periodontal disease is associated with cardiovascular disease (CVD) but it is unknown if periodontal disease severity is associated with asymptomatic carotid plaque. The aim of the current population-based, observational study was to investigate if signs of periodontal disease are associated with the occurrence of carotid plaque and total plaque area (TPA). METHODS: The Malmö Offspring Study (MOS) is a population-based study. MOS participants underwent a thorough cardiovascular phenotyping, including carotid ultrasonography. The Malmö Offspring Dental Study (MODS) invited participants of MOS for dental examination, including periodontal charting. Multivariable regression models were used to analyse the presence of carotid plaque and TPA in relation to periodontal parameters. RESULTS: In all, 831 MODS participants were recruited, out of which 495 belonged to the children generation with mean age of 53 years, 63% had carotid plaque and 38% had moderate or severe periodontal disease. In models adjusted for CVD risk factors, the OR for having carotid plaque in subjects with vs without periodontal disease was 1.75 (95% CI: 1.11-2.78). In a linear model with TPA as dependent and number of periodontal pockets ≥ 4 mm as independent variable, the adjusted beta-coefficient was 0.34 mm2 (95% CI 0.16-0.52). CONCLUSION: Individuals within the highest quartile of periodontal pockets are expected to have 9 mm2 larger TPA compared to those without pockets. Our results suggest that intervention studies addressing periodontal disease could be useful for prevention of CVD.

Subclinical atherosclerosis and its progression are modulated by PLIN2 through a feed-forward loop between LXR and autophagy.

BACKGROUND: Hyperlipidaemia is a major risk factor for cardiovascular disease, and atherosclerosis is the underlying cause of both myocardial infarction and stroke. We have previously shown that the Pro251 variant of perilipin-2 reduces plasma triglycerides and may therefore be beneficial to reduce atherosclerosis development. OBJECTIVE: We sought to delineate putative beneficial effects of the Pro251 variant of perlipin-2 on subclinical atherosclerosis and the mechanism by which it acts. METHODS: A pan-European cohort of high-risk individuals where carotid intima-media thickness has been assessed was adopted. Human primary monocyte-derived macrophages were prepared from whole blood from individuals recruited by perilipin-2 genotype or from buffy coats from the Karolinska University hospital blood central. RESULTS: The Pro251 variant of perilipin-2 is associated with decreased intima-media thickness at baseline and over 30 months of follow-up. Using human primary monocyte-derived macrophages from carriers of the beneficial Pro251 variant, we show that this variant increases autophagy activity, cholesterol efflux and a controlled inflammatory response. Through extensive mechanistic studies, we demonstrate that increase in autophagy activity is accompanied with an increase in liver-X-receptor (LXR) activity and that LXR and autophagy reciprocally activate each other in a feed-forward loop, regulated by CYP27A1 and 27OH-cholesterol. CONCLUSIONS: For the first time, we show that perilipin-2 affects susceptibility to human atherosclerosis through activation of autophagy and stimulation of cholesterol efflux. We demonstrate that perilipin-2 modulates levels of the LXR ligand 27OH-cholesterol and initiates a feed-forward loop where LXR and autophagy reciprocally activate each other; the mechanism by which perilipin-2 exerts its beneficial effects on subclinical atherosclerosis.

Phenotypic and genotypic differences between Indian and Scandinavian women with gestational diabetes mellitus.

OBJECTIVE: Gestational diabetes mellitus (GDM) is a transient form of diabetes characterized by impaired insulin secretion and action during pregnancy. Population-based differences in prevalence exist which could be explained by phenotypic and genetic differences. The aim of this study was to examine these differences in pregnant women from Punjab, India and Scandinavia. METHODS: Eighty-five GDM/T2D loci in European and/or Indian populations from previous studies were assessed for association with GDM based on Swedish GDM criteria in 4018 Punjabi Indian and 507 Swedish pregnant women. Selected loci were replicated in Scandinavian cohorts, Radiel (N = 398, Finnish) and STORK/STORK-G (N = 780, Norwegian). RESULTS: Punjabi Indian women had higher GDM prevalence, lower insulin secretion and better insulin sensitivity than Swedish women. There were significant frequency differences of GDM/T2D risk alleles between both populations. rs7178572 at HMG20A, previously associated with GDM in South Indian and European women, was replicated in North Indian women. The T2D risk SNP rs11605924 in the CRY2 gene was associated with increased GDM risk in Scandinavian but decreased GDM risk in Punjabi Indian women. No other overlap was seen between GDM loci in both populations. CONCLUSIONS: Gestational diabetes mellitus is more common in Indian than Swedish women, which partially can be attributed to differences in insulin secretion and action. There was marked heterogeneity in the GDM phenotypes between the populations which could only partially be explained by genetic differences.

Plasma levels of the proprotein convertase furin and incidence of diabetes and mortality.

BACKGROUND: Diabetes mellitus is linked to premature mortality of virtually all causes. Furin is a proprotein convertase broadly involved in the maintenance of cellular homeostasis; however, little is known about its role in the development of diabetes mellitus and risk of premature mortality. OBJECTIVES: To test if fasting plasma concentration of furin is associated with the development of diabetes mellitus and mortality. METHODS: Overnight fasted plasma furin levels were measured at baseline examination in 4678 individuals from the population-based prospective Malmö Diet and Cancer Study. We studied the relation of plasma furin levels with metabolic and hemodynamic traits. We used multivariable Cox proportional hazards models to investigate the association between baseline plasma furin levels and incidence of diabetes mellitus and mortality during 21.3-21.7 years follow-up. RESULTS: An association was observed between quartiles of furin concentration at baseline and body mass index, blood pressure and plasma concentration of glucose, insulin, LDL and HDL cholesterol (|0.11| ≤ ß ≤ |0.31|, P < 0.001). Plasma furin (hazard ratio [HR] per one standard deviation increment of furin) was predictive of future diabetes mellitus (727 events; HR = 1.24, CI = 1.14-1.36, P < 0.001) after adjustment for age, sex, body mass index, systolic and diastolic blood pressure, use of antihypertensive treatment, alcohol intake and fasting plasma level of glucose, insulin and lipoproteins cholesterol. Furin was also independently related to the risk of all-cause mortality (1229 events; HR = 1.12, CI = 1.05-1.19, P = 0.001) after full multivariable adjustment. CONCLUSION: Individuals with high plasma furin concentration have a pronounced dysmetabolic phenotype and elevated risk of diabetes mellitus and premature mortality.

Association between systemic leptin and neurotensin concentration in adult individuals with and without type 2 diabetes mellitus.

PURPOSE: Leptin is an adipokine which regulates appetite and energy balance through a mechanism partially mediated by neurotensin (NT) in central nervous system. Besides acting as a neurotransmitter, NT is expressed in human intestine where it promotes fat absorption and its circulating levels associate with obesity, type 2 diabetes mellitus (T2DM) and cardiovascular disease. Whether a relation exists between circulating leptin and NT levels has not been investigated yet. The aim of this study was to test the hypothesis of an association between plasma leptin and NT concentration in adults with or without T2DM. METHODS: We recruited a population of 72 subjects (M/F: 39/33; age: 49.5 ± 10.6 years; BMI: 26.5 ± 4.7 kg/m2) including individuals with T2DM (n = 32) referring to our Diabetes Outpatient Clinics, Sapienza University of Rome, and healthy controls. Study participants underwent metabolic characterization; plasma leptin was measured by MILLIPLEX, Luminex, and proneurotensin (proNT), a stable precursor of NT, by chemiluminometric sandwich immunoassay. RESULTS: Circulating median (25°-75°) leptin levels were 2.75 (1.27-4.93) ng/mL and did not differ between T2DM and non-diabetic subjects. Leptin concentration directly correlated with proNT (r = 0.41; p = 0.015); higher leptin levels were also associated with age, male gender, obesity, higher HOMA-IR, systolic blood pressure and C-reactive protein. Belonging to the highest pro-NT quartile correlated with greater leptin levels independent of age, gender and other confounders (r2 = 0.82, p = 0.02). CONCLUSIONS: Circulating leptin is associated with higher proNT levels independent of diabetes, obesity and metabolic syndrome components; besides its effects on central leptin signaling, NT may influence energy balance by modulating circulating leptin concentration likely through a mechanism involving gut fat absorption.

Plasma stem cell factor levels are associated with risk of cardiovascular disease and death.

OBJECTIVE: Stem cell factor (SCF) is a key growth factor for several types of stem and progenitor cells. There is experimental evidence that such cells are of importance for maintaining the integrity of the cardiovascular system. We investigated the association between circulating levels of SCF and risk for development of cardiovascular events and death. METHODS: SCF was analysed by the proximity extension assay technique in plasma from 4742 subjects participating in the Malmö Diet and Cancer Study. Cardiovascular events and death were monitored through national registers with a mean follow-up time of 19.2 years. RESULTS: Subjects with high baseline levels of SCF had lower cardiovascular (n = 340) and all-cause mortality (n = 1159) as well as a lower risk of heart failure (n = 177), stroke (n = 318) and myocardial infarction (n = 452). Smoking, diabetes and high alcohol consumption were associated with lower levels of SCF. Single nucleotide polymorphisms in the gene region encoding PDX1 C-terminal inhibiting factor 1 (PCIF1) and matrix metalloproteinase-9 were associated with plasma SCF levels. The highest SCF quartile remained independently associated with a lower risk of a lower risk of cardiovascular [hazard ratio and 95% confidence interval 0.59 (0.43-0.81)] and all-cause mortality [0.68 (0.57-0.81)], heart failure [0.50 (0.31-0.80)] and stroke [0.66 (0.47-0.92)], but not with MI [0.96 (0.72-1.27)] as compared with the lowest quartile when adjusting for traditional cardiovascular risk factors in Cox proportional hazard regression models. CONCLUSIONS: This prospective population-based study demonstrates that subjects with high levels of SCF have a lower risk of cardiovascular events and death. The findings provide clinical support for a protective role of SCF in maintaining cardiovascular integrity.

Inverse relationship between a genetic risk score of 31 BMI loci and weight change before and after reaching middle age.

BACKGROUND/OBJECTIVE: Genome-wide-association studies have identified numerous body mass index (BMI)-associated variants, but it is unclear how these relate to weight gain in adults at different ages. METHODS: We examined the association of a genetic risk score (GRS), consisting of 31 BMI-associated variants, with an annual weight change (AWC) and a substantial weight gain (SWG) of 10% by comparing self-reported weight at 20 years (y) with baseline weight (mean: 58 y; s.d.: 8 y) in 21407 participants from the Malmö Diet and Cancer Study (MDCS), and comparing baseline weight to weight at follow-up (mean: 73 y; s.d.: 6 y) among 2673 participants. Association between GRS and AWG and SWG was replicated in 4327 GLACIER (Gene x Lifestyle interactions And Complex traits Involved in Elevated disease Risk) participants (mean: 45 y; s.d.: 7 y) with 10 y follow-up. Cohort-specific results were pooled by fixed-effect meta-analyses. RESULTS: In MDCS, the GRS was associated with increased AWC (ß: 0.003; s.e: 0.01; P: 7 × 10(-8)) and increased odds for SWG (odds ratio (OR) 1.01 (95% confidence interval (CI): 1.00, 1.02); P: 0.013) per risk-allele from age 20y, but unexpectedly with decreased AWC (ß: -0.006; s.e: 0.002; P: 0.009) and decreased odds for SWG OR 0.96 (95% CI: 0.93, 0.98); P: 0.001) between baseline and follow-up. Effect estimates from age 20 y to baseline differed significantly from those from baseline to follow-up (P: 0.0002 for AWC and P: 0.0001 for SWG). Similar to MDCS, the GRS was associated with decreased odds for SWG OR 0.98 (95% CI: 0.96, 1.00); P: 0.029) from baseline to follow-up in GLACIER. In meta-analyses (n=7000), the GRS was associated with decreased AWC (ß: -0.005; s.e.m. 0.002; P: 0.002) and decreased odds for SWG OR 0.97 (95% CI: 0.96, 0.99); P: 0.001) per risk-allele. CONCLUSIONS: Our results provide convincing evidence for a paradoxical inversed relationship between a high number of BMI-associated risk-alleles and less weight gain during and after middle-age, in contrast to the expected increased weight gain seen in younger age.

Genetics of coronary heart disease: towards causal mechanisms, novel drug targets and more personalized prevention.

Coronary heart disease (CHD) is an archetypical multifactorial disorder that is influenced by genetic susceptibility as well as both modifiable and nonmodifiable risk factors, and their interactions. Advances during recent years in the field of multifactorial genetics, in particular genomewide association studies (GWASs) and their meta-analyses, have provided the statistical power to identify and replicate genetic variants in more than 50 risk loci for CHD and in several hundreds of loci for cardiometabolic risk factors for CHD such as blood lipids and lipoproteins. Although for a great majority of these loci both the causal variants and mechanisms remain unknown, progress in identifying the causal variants and underlying mechanisms has already been made for several genetic loci. Furthermore, identification of rare loss-of-function variants in genes such as PCSK9, NPC1L1, APOC3 and APOA5, which cause a markedly decreased risk of CHD and no adverse side effects, illustrates the power of translating genetic findings into novel mechanistic information and provides some optimism for the future of developing novel drugs, given the many genes associated with CHD in GWASs. Finally, Mendelian randomization can be used to reveal or exclude causal relationships between heritable biomarkers and CHD, and such approaches have already provided evidence of causal relationships between CHD and LDL cholesterol, triglycerides/remnant particles and lipoprotein(a), and indicated a lack of causality for HDL cholesterol, C-reactive protein and lipoprotein-associated phospholipase A2. Together, these genetic findings are beginning to lead to promising new drug targets and novel interventional strategies and thus have great potential to improve prevention, prediction and therapy of CHD.

Variability in the CIITA gene interacts with HLA in multiple sclerosis.

The human leukocyte antigen (HLA) is the main genetic determinant of multiple sclerosis (MS) risk. Within the HLA, the class II HLA-DRB1*15:01 allele exerts a disease-promoting effect, whereas the class I HLA-A*02 allele is protective. The CIITA gene is crucial for expression of class II HLA molecules and has previously been found to associate with several autoimmune diseases, including MS and type 1 diabetes. We here performed association analyses with CIITA in 2000 MS cases and up to 6900 controls as well as interaction analysis with HLA. We find that the previously investigated single-nucleotide polymorphism rs4774 is associated with MS risk in cases carrying the HLA-DRB1*15 allele (P=0.01, odds ratio (OR): 1.21, 95% confidence interval (CI): 1.04-1.40) or the HLA-A*02 allele (P=0.01, OR: 1.33, 95% CI: 1.07-1.64) and that these associations are independent of the adjacent confirmed MS susceptibility gene CLEC16A. We also confirm interaction between rs4774 and HLA-DRB1*15:01 such that individuals carrying the risk allele for rs4774 and HLA-DRB1*15:01 have a higher than expected risk for MS. In conclusion, our findings support previous data that variability in the CIITA gene affects MS risk, but also that the effect is modulated by MS-associated HLA haplotypes. These findings further underscore the biological importance of HLA for MS risk.

Adipose tissue is inflamed in NAFLD due to obesity but not in NAFLD due to genetic variation in PNPLA3.

AIMS/HYPOTHESIS: The rs738409 C>G single-nucleotide polymorphism in PNPLA3 leads to a missense mutation (I148M) which increases liver fat but does not cause insulin resistance. We hypothesised that patients with non-alcoholic fatty liver disease (NAFLD) due to the PNPLA3 variant ('PNPLA3 NAFLD' = PNPLA3-148MM) do not have adipose tissue (AT) inflammation in contrast with those with NAFLD due to obesity ('obese NAFLD'). METHODS: Biopsy specimens of AT were taken, and PNPLA3 genotype and liver fat ((1)H-magnetic resonance spectroscopy) were determined in 82 volunteers, who were divided into groups based on either median BMI (obese 36.2 ± 0.7 kg/m(2); non-obese 26.0 ± 0.4 kg/m(2)) or PNPLA3 genotype. All groups were similar with respect to age and sex. The PNPLA3 subgroups were equally obese (PNPLA3-148MM, 31.1 ± 1.3 kg/m(2); PNPLA3-148II, 31.2 ± 0.8 kg/m(2)), while the obese and non-obese subgroups had similar PNPLA3 genotype distribution. Gene expression of proinflammatory (MCP-1, CD68) and anti-inflammatory (Twist1, ADIPOQ) markers was measured using quantitative real-time RT-PCR. RESULTS: Liver fat was similarly increased in obese NAFLD (9.5 ± 1.3% vs 5.1 ± 0.9%, obese vs non-obese, p = 0.007) and PNPLA3 NAFLD (11.4 ± 1.7% vs 5.3 ± 0.8%, PNPLA3-148MM vs PNPLA3-148II, p < 0.001). Fasting serum insulin was higher in the obese than the non-obese group (76 ± 6 vs 47 ± 6 pmol/l, p < 0.001), but similar in PNPLA3-148MM and PNPLA3-148II (60 ± 8 vs 62 ± 5 pmol/l, NS). In obese vs non-obese, MCP-1 and CD68 mRNAs were upregulated, whereas those of Twist1 and ADIPOQ were significantly downregulated. AT gene expression of MCP-1, CD68, Twist1 and ADIPOQ was similar in PNPLA3-148MM and PNPLA3-148II groups. CONCLUSIONS/INTERPRETATION: PNPLA3 NAFLD is characterised by an increase in liver fat but no insulin resistance or AT inflammation, while obese NAFLD has all three of these features.

Age-dependent variation of genotypes in MHC II transactivator gene (CIITA) in controls and association to type 1 diabetes.

The major histocompatibility complex class II transactivator (CIITA) gene (16p13) has been reported to associate with susceptibility to multiple sclerosis, rheumatoid arthritis and myocardial infarction, recently also to celiac disease at genome-wide level. However, attempts to replicate association have been inconclusive. Previously, we have observed linkage to the CIITA region in Scandinavian type 1 diabetes (T1D) families. Here we analyze five Swedish T1D cohorts and a combined control material from previous studies of CIITA. We investigate how the genotype distribution within the CIITA gene varies depending on age, and the association to T1D. Unexpectedly, we find a significant difference in the genotype distribution for markers in CIITA (rs11074932, P=4 × 10(-5) and rs3087456, P=0.05) with respect to age, in the collected control material. This observation is replicated in an independent cohort material of about 2000 individuals (P=0.006, P=0.007). We also detect association to T1D for both markers, rs11074932 (P=0.004) and rs3087456 (P=0.001), after adjusting for age at sampling. The association remains independent of the adjacent T1D risk gene CLEC16A. Our results indicate an age-dependent variation in CIITA allele frequencies, a finding of relevance for the contrasting outcomes of previously published association studies.

Role of TCF7L2 risk variant and dietary fibre intake on incident type 2 diabetes.

AIMS/HYPOTHESIS: The T allele of transcription factor 7-like 2 gene variant, TCF7L2 rs7903146, increases the risk of type 2 diabetes by 40-50%. As TCF7L2 rs7903146 has been associated with diminished incretin effect we investigated whether interaction between dietary intake of carbohydrate, fat, protein or fibre and this variant affects the risk of type 2 diabetes. METHODS: A cohort of 24,799 non-diabetic individuals from the Malmö Diet and Cancer Study (MDCS), with dietary data obtained by a modified diet history method, were followed up for 12 years, with 1,649 recordings of incident type 2 diabetes made. Risk of type 2 diabetes in strata of diet quintiles was analysed prospectively adjusting for potential confounders. Cross-sectional analyses were performed on baseline fasting glucose and HbA(1c) levels in a subset of 5,216 randomly selected individuals from the MDCS. RESULTS: The elevated risk of type 2 diabetes with rs7903146 (OR 1.44, 95% CI 1.33, 1.56, p = 4.6 × 10(-19)) increased with higher intake of dietary fibre (OR 1.24, 95% CI 1.04, 1.47 to OR 1.56, 95% CI 1.31, 1.86 from the lowest to highest quintile; p (interaction) = 0.049). High intake of dietary fibre was inversely associated with diabetes incidence only among CC genotype carriers (OR 0.74, 95% CI 0.58, 0.94 per quintile, p = 0.025). The T allele was associated with 0.027% elevated HbA(1c) (p = 0.02) and this effect increased with higher intake of fibre (from -0.021% to 0.079% for the lowest to the highest quintile, p (interaction) = 0.02). Each quintile of higher fibre intake was associated with lower HbA(1c) levels among CC and CT but not among TT genotype carriers (-0.036%, p = 6.5 × 10(-7); -0.023%, p = 0.009; and 0.012%, p = 0.52, respectively). CONCLUSIONS/INTERPRETATION: Our study suggests that dietary fibre intake may modify the association between TCF7L2 rs7903146 and incidence of type 2 diabetes, and that higher fibre intake may associate with protection from type 2 diabetes only among non-risk allele carriers.

Intake levels of dietary long-chain PUFAs modify the association between genetic variation in FADS and LDL-C.

Polymorphisms of the FA desaturase (FADS) gene cluster have been associated with LDL, HDL, and triglyceride concentrations. Because FADS converts α-linolenic acid (ALA) and linoleic acid into PUFAs, we investigated the interaction between different PUFA intakes and the FADS polymorphism rs174547 (T>C) on fasting blood lipid and lipoprotein concentrations. We included 4,635 individuals (60% females, 45-68 years) from the Swedish population-based Malmö Diet and Cancer cohort. Dietary intakes were assessed by a modified diet history method including 7-day registration of cooked meals. The C-allele of rs174547 was associated with lower LDL concentration (P = 0.03). We observed significant interaction between rs174547 and long-chain ω-3 PUFA intakes on LDL (P = 0.01); the C-allele was only associated with lower LDL among individuals in the lowest tertile of long-chain ω-3 PUFA intakes (P < 0.001). In addition, significant interaction was observed between rs174547 and the ratio of ALA and linoleic FA intakes on HDL (P = 0.03). However, no significant associations between the C-allele and HDL were detected within the intake tertiles of the ratio. Our findings suggest that dietary intake levels of different PUFAs modify the associated effect of genetic variation in FADS on LDL and HDL.

Association between fat intake, physical activity and mortality depending on genetic variation in FTO.

OBJECTIVE: We wanted to explore if FTO genotype interacts with fat intake, or leisure-time physical activity, on fat mass, lean mass and mortality. SUBJECTS AND METHODS: Among 22,799 individuals (44-74 years) in the population-based Malmö diet and cancer cohort that were genotyped for rs9939609 in FTO and had information on dietary intake (from a modified diet history method) and no history of diabetes, cancer or cardiovascular disease, 2255 deaths (including 1100 cancer and 674 cardiovascular deaths) occurred during 12.0 years of follow-up. Leisure-time physical activity was determined from a list of 17 different physical activities in a questionnaire. Body composition was measured using bioelectric impedance method. RESULTS: FTO genotype associated strongly with both fat mass and lean mass (P(trend) <1 × 10(-16) for both) but we found only significant interactions with fat intake, or physical activity, on fat mass (P(interaction)=0.01 and 0.004). No significant interaction between FTO genotype and fat intake (P(interaction)=0.72), or leisure-time physical activity (P(interaction)=0.07), on total mortality were observed. However, we observed a significant interaction between leisure-time physical activity and FTO genotype on cardiovascular mortality (P(interaction)=0.03). The highest vs lowest quintile of physical activity was associated with 46% (95% confidence interval, 17-64%) reduced cardiovascular mortality among TT-carriers (P(trend)=0.004), and 11% reduced cardiovascular mortality among A-allele carriers (P(trend)=0.68). CONCLUSION: Our results indicate that FTO genotype associates with both fat mass and lean mass, but the level of fat intake and physical activity only modify the association with fat mass. In addition, FTO genotype may modify the association between physical activity and cardiovascular mortality.

A common variant in PNPLA3, which encodes adiponutrin, is associated with liver fat content in humans.

AIMS/HYPOTHESIS: It has recently been suggested that the rs738409 G allele in PNPLA3, which encodes adiponutrin, is strongly associated with increased liver fat content in three different ethnic groups. The aims of the present study were as follows: (1) to try to replicate these findings in European individuals with quantitative measures of hepatic fat content; (2) to study whether the polymorphism influences hepatic and adipose tissue insulin sensitivity; and (3) to investigate whether PNPLA3 expression is altered in the human fatty liver. METHODS: We genotyped 291 Finnish individuals in whom liver fat had been measured using proton magnetic resonance spectroscopy. Hepatic PNPLA3 expression was measured in 32 participants. Hepatic and adipose tissue insulin sensitivities were measured using a euglycaemic-hyperinsulinaemic (insulin infusion 0.3 mU kg(-1) min(-1)) clamp technique combined with infusion of [3-(3)H]glucose in 109 participants. RESULTS: The rs738409 G allele in PNPLA3 was associated with increased quantitative measures of liver fat content (p = 0.011) and serum aspartate aminotransferase concentrations (p = 0.002) independently of age, sex and BMI. Fasting serum insulin and hepatic and adipose tissue insulin sensitivity were related to liver fat content independently of genotype status. PNPLA3 mRNA expression in the liver was positively related to obesity (r = 0.62, p < 0.0001) and to liver fat content (r = 0.58, p = 0.025) in participants who were not morbidly obese (BMI < 40 kg/m(2)). CONCLUSIONS/INTERPRETATION: A common variant in PNPLA3 increases the risk of hepatic steatosis in humans.

The search for putative unifying genetic factors for components of the metabolic syndrome.

AIMS/HYPOTHESIS: The metabolic syndrome is a cluster of factors contributing to increased risk of cardiovascular disease and type 2 diabetes but unifying mechanisms have not been identified. Our aim was to study whether common variations in 17 genes previously associated with type 2 diabetes or components of the metabolic syndrome and variants in nine genes with inconsistent association with at least two components of the metabolic syndrome would also predict future development of components of the metabolic syndrome, individually or in combination. METHODS: Genetic variants were studied in a large prospective study of 16,143 non-diabetic individuals (mean follow-up time 23 years) from the Malmö Preventive Project. In this study, development of at least three of obesity (BMI >or= 30 kg/m(2)), dyslipidaemia (triacylglycerol >or= 1.7 mmol/l and/or lipid-lowering treatment), hypertension (blood pressure >or= 140/90 mmHg and/or antihypertensive medication) and hyperglycaemia (fasting plasma glucose >or= 5.6 mmol/l and/or known diabetes) was defined as development of the metabolic syndrome. The risk of developing at least three components of the metabolic syndrome or the individual components was calculated by logistic regression adjusted for age at baseline, follow-up time and sex. RESULTS: Polymorphisms in TCF7L2 (rs7903146, OR 1.10, 95% CI 1.04-1.17, p = 0.00097), FTO (rs9939609, OR 1.08, 95% CI 1.02-1.14, p = 0.0065), WFS1 (rs10010131, OR 1.07, 95% CI 1.02-1.13, p = 0.0078) and IGF2BP2 (rs4402960, OR 1.07, 95% CI 1.01-1.13, p = 0.021) predicted the development of at least three components of the metabolic syndrome in both univariate and multivariate analysis; in the case of TCF7L2, WFS1 and IGF2BP this was due to their association with hyperglycaemia (p < 0.00001, p = 0.0033 and p = 0.027, respectively) and for FTO it was due to its association with obesity (p = 0.004). A polymorphism in the GCKR gene predicted dyslipidaemia (rs1260326, OR 1.15, 95% CI 1.09-1.22, p < 0.00001) but not the metabolic syndrome. None of the studied polymorphisms was associated with more than two components of the metabolic syndrome. A composite genotype score of the 17 polymorphisms associated with type 2 diabetes predicted the development of at least three components of the metabolic syndrome (OR 1.04, p < 0.00001) and the development of hyperglycaemia (OR 1.06, p < 0.00001). Carriers of >or=19 risk alleles had 51 and 72% increased risk of developing at least three components of the metabolic syndrome and hyperglycaemia, respectively, compared with carriers of

The variable clinical phenotype of liver glycogen synthase deficiency.

We report two new cases of liver glycogen synthase deficiency (GSD0). The first patient presented at the age of 8 months with recurrent hypoglycemic seizures. The second patient presented at 14 months with asymptomatic incidental hyperglycemia. Glucose monitoring in both patients revealed daily fluctuations from fasting hypoglycemia to postprandial hyperglycemia. Genetic analysis of the GYS2 gene confirmed the diagnosis. GSD0 is more common than previously assumed. Recognition of the variable phenotype spectrum of GSD0 and routine analysis of GYS2 are essential for the correct diagnosis.

A polymorphism in the adiponectin gene influences adiponectin expression levels in visceral fat in obese subjects.

OBJECTIVE: Reduced serum adiponectin levels have been found in obesity and type 2 diabetes and variations in the adiponectin gene (APM1) have been associated with type 2 diabetes and features of the metabolic syndrome in different populations. STUDY DESIGN: Here, we investigated the expression of APM1 in adipose tissue and studied the relationship between variation in APM1 expression, the APM1 G276T polymorphism, the common PPARG Pro12Ala polymorphism and clinical features of 36 morbidly obese (body mass index (BMI) 41.5 +/- 4.9 kg/m2) nondiabetic subjects. RESULTS: APM1 mRNA expression in visceral fat was correlated with serum adiponectin levels (r = 0.54, P = 0.012). In visceral, but not in subcutaneous, adipose tissue APM1 mRNA level was 38% higher among carriers of the APM1 G276T T allele (G/T and T/T) than among carriers of the G/G genotype (0.91 +/- 0.06 for G/T and T/T carriers vs 0.66 +/- 0.09 for G/G carriers, P = 0.013). Carriers of the T allele also had significantly higher body fat percent compared to G/G carriers (65 +/- 6 vs 56 +/- 10%, P = 0.011). CONCLUSION: Our results indicate that genetic variation in APM1 influences the expression of the gene in visceral adipose tissue and suggest a potential role for such variation in regulation of body fat accumulation in obese subjects.