👤 Andrea von Berg

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy characterized by ventricular arrhythmias and sudden death. Currently 60% of patients meeting Task Force Criteria (TFC) have an identifiable mutation in one of the desmosomal genes. As much overlap is described between other cardiomyopathies and ARVC, we examined the prevalence of rare, possibly pathogenic sarcomere variants in the ARVC population. One hundred and thirty-seven (137) individuals meeting 2010 TFC for a diagnosis of ARVC, negative for pathogenic desmosomal variants, TMEM43, SCN5A, and PLN were screened for variants in the sarcomere genes (ACTC1, MYBPC3, MYH7, MYL2, MYL3, TNNC1, TNNI3, TNNT2, and TPM1) through either clinical or research genetic testing. Six probands (6/137, 4%) were found to carry rare variants in the sarcomere genes. These variants have low prevalence in controls, are predicted damaging by Polyphen-2, and some of the variants are known pathogenic hypertrophic cardiomyopathy mutations. Sarcomere variant carriers had a phenotype that did not differ significantly from desmosomal mutation carriers. As most of these probands were the only affected individuals in their families, however, segregation data are noninformative. These data show variants in the sarcomere can be identified in individuals with an ARVC phenotype. Although rare and predicted damaging, proven functional and segregational evidence that these variants can cause ARVC is lacking. Therefore, caution is warranted in interpreting these variants when identified on large next-generation sequencing panels for cardiomyopathies. Show less

The clinical outcomes of noncompaction cardiomyopathy (NCCM) range from asymptomatic to heart failure, arrhythmias, and sudden cardiac death. Genetics play an important role in NCCM. This study investigated the correlations among genetics, clinical features, and outcomes in adults and children diagnosed with NCCM. A retrospective multicenter study from 4 cardiogenetic centers in the Netherlands classified 327 unrelated NCCM patients into 3 categories: 1) genetic, with a mutation in 32% (81 adults; 23 children) of patients; 2) probably genetic, familial cardiomyopathy without a mutation in 16% (45 adults; 8 children) of patients; or 3) sporadic, no family history, without mutation in 52% (149 adults; 21 children) of patients. Clinical features and major adverse cardiac events (MACE) during follow-up were compared across the children and adults. MYH7, MYBPC3, and TTN mutations were the most common mutations (71%) found in genetic NCCM. The risk of having reduced left ventricular (LV) systolic dysfunction was higher for genetic patients compared with the probably genetic and sporadic cases (p = 0.024), with the highest risk in patients with multiple mutations and TTN mutations. Mutations were more frequent in children (p = 0.04) and were associated with MACE (p = 0.025). Adults were more likely to have sporadic NCCM. High risk for cardiac events in children and adults was related to LV systolic dysfunction in mutation carriers, but not in sporadic cases. Patients with MYH7 mutations had low risk for MACE (p = 0.03). NCCM is a heterogeneous condition, and genetic stratification has a role in clinical care. Distinguishing genetic from nongenetic NCCM complements prediction of outcome and may lead to management and follow-up tailored to genetic status. Show less

Activation of brown adipose tissue (BAT) reduces both hyperlipidemia and atherosclerosis by increasing the uptake of triglyceride-derived fatty acids by BAT, accompanied by formation and clearance of lipoprotein remnants. We tested the hypothesis that the hepatic uptake of lipoprotein remnants generated by BAT activation would be accelerated by concomitant statin treatment, thereby further reducing hypercholesterolemia and atherosclerosis. APOE*3-Leiden.CETP mice were fed a Western-type diet and treated without or with the selective β3-adrenergic receptor (AR) agonist CL316,243 that activates BAT, atorvastatin (statin) or both. β3-AR agonism increased energy expenditure as a result of an increased fat oxidation by activated BAT, which was not further enhanced by statin addition. Accordingly, statin treatment neither influenced the increased uptake of triglyceride-derived fatty acids from triglyceride-rich lipoprotein-like particles by BAT nor further lowered plasma triglyceride levels induced by β3-AR agonism. Statin treatment increased the hepatic uptake of the formed cholesterol-enriched remnants generated by β3-AR agonism. Consequently, statin treatment further lowered plasma cholesterol levels. Importantly, statin, in addition to β3-AR agonism, also further reduced the atherosclerotic lesion size as compared to β3-AR agonism alone, without altering lesion severity and composition. Statin treatment accelerates the hepatic uptake of remnants generated by BAT activation, thereby increasing the lipid-lowering and anti-atherogenic effects of BAT activation in an additive fashion. We postulate that, in clinical practice, combining statin treatment with BAT activation is a promising new avenue to combat hyperlipidemia and cardiovascular disease. Show less

We evaluated possible changes in VLDLcharacteristics, and metabolic related factors, in MetS-associated NAFLD and accompanying liver fibrosis. We studied 36 MetS patients with biopsy-proven NAFLD (MetS+NAFLD) and 24 MetS without ultrasound NAFLD evidence. Further, MetS+NAFLD was sub-divided according to fibrosis stage into, non-to-moderate (F0-F2, n=27) and severe (F3-F4, n=9) fibrosis. We measured: lipid profile, VLDL composition and size (size exclusion-HPLC), CETP and lipoprotein lipase (LPL) activities and adiponectin. Additionally, in MetS+NAFLD type IV collagen 7S domain was measured. MetS+NAFLD showed increased VLDL-mass, VLDL particle number, VLDL-triglyceride% and large VLDL-% (p<0.04). CETP activity tended to increase in MetS+NAFLD (p=0.058), while LPL activity was unchanged. Moreover, in MetS+NAFLD, adiponectin was decreased (p<0.001), and negatively correlated with VLDL-mass and VLDL particle number (p<0.05), independently of insulin-resistance. Within MetS+NAFLD group, despite greater insulin-resistance, patients with severe fibrosis showed lower plasma triglycerides, VLDL-mass, VLDL-triglyceride%, large VLDL-% and CETP activity (p<0.05), while type IV collagen was increased (p=0.009) and inversely correlated with large VLDL-% (p=0.045). In MetS, NAFLD is associated with larger and triglyceride over-enriched circulating VLDLs, of greater atherogenicity. However, when NAFLD progresses to severe fibrosis, circulating VLDL features apparently improved, probably due to early alterations in hepatic synthetic function. Show less

Fetal akinesia deformation sequence (FADS) is a clinically and genetically heterogenous disorder. In this study, the different sonographic abnormalities are described in a larger number of affected fetuses. This retrospective study included 79 cases of suspected FADS observed in our tertiary referral center between January 2001 and February 2015. Electronic stored reports and images of the examination were reviewed as well as autopsy reports and pediatric charts. In the study population (mean gestational age 23 + 4 weeks) consanguinity, multiple miscarriages or positive family history were present in 31.6 % of cases. Abnormalities of the facial profile (58.3 %) and ankle joint (83.6 %) were detected in the majority of cases. Contractures variably involved knee-, ankle-, wrist- and elbow joint and fingers with no distinct patterns. Additional malformations, most commonly of the brain, were found in 44.3 % of cases. Diagnosis before 20 weeks was associated with nuchal edema in 62.5 and hydrops in 31.3 %. In fetuses evaluated later than 24 weeks, IUGR, increased amniotic fluid or thorax hypoplasia were diagnosed, in 31, 58.8 and 37.9 %, respectively. Termination of pregnancy was requested in 86.1 %, 11 (13.9 %) children were live born. No underlying genetic cause was established, but in one asymptomatic mother myasthenia gravis was revealed. Fetal akinesia presents with heterogeneous sonographic findings, mostly affecting the profile, elbow-, knee-, ankle joint, wrists and fingers; in most of cases of sporadic nature. Whereas hydrops fetalis and nuchal edema were earlier signs, thorax hypoplasia, polyhydramnios and IUGR were found later in pregnancy. Show less

The ST-segment and adjacent T-wave (ST-T wave) amplitudes of the electrocardiogram are quantitative characteristics of cardiac repolarization. Repolarization abnormalities have been linked to ventricular arrhythmias and sudden cardiac death. We performed the first genome-wide association meta-analysis of ST-T-wave amplitudes in up to 37 977 individuals identifying 71 robust genotype-phenotype associations clustered within 28 independent loci. Fifty-four genes were prioritized as candidates underlying the phenotypes, including genes with established roles in the cardiac repolarization phase (SCN5A/SCN10A, KCND3, KCNB1, NOS1AP and HEY2) and others with as yet undefined cardiac function. These associations may provide insights in the spatiotemporal contribution of genetic variation influencing cardiac repolarization and provide novel leads for future functional follow-up. Show less

We conducted a genome-wide association study of essential tremor, a common movement disorder characterized mainly by a postural and kinetic tremor of the upper extremities. Twin and family history studies show a high heritability for essential tremor. The molecular genetic determinants of essential tremor are unknown. We included 2807 patients and 6441 controls of European descent in our two-stage genome-wide association study. The 59 most significantly disease-associated markers of the discovery stage were genotyped in the replication stage. After Bonferroni correction two markers, one (rs10937625) located in the serine/threonine kinase STK32B and one (rs17590046) in the transcriptional coactivator PPARGC1A were associated with essential tremor. Three markers (rs12764057, rs10822974, rs7903491) in the cell-adhesion molecule CTNNA3 were significant in the combined analysis of both stages. The expression of STK32B was increased in the cerebellar cortex of patients and expression quantitative trait loci database mining showed association between the protective minor allele of rs10937625 and reduced expression in cerebellar cortex. We found no expression differences related to disease status or marker genotype for the other two genes. Replication of two lead single nucleotide polymorphisms of previous small genome-wide association studies (rs3794087 in SLC1A2, rs9652490 in LINGO1) did not confirm the association with essential tremor. Show less

Sudden cardiac arrest (SCA) ranks among the most common causes of death worldwide. Because SCA is most often lethal, yet mostly occurs in individuals without previously known cardiac disease, the identification of patients at risk for SCA could save many lives. In unselected SCA victims from the community, common genetic variants (which are not disease-causing per se, but may increase susceptibility to ventricular fibrillation) are found to be associated with increased SCA risk. However, whether rare genetic variants contribute to SCA risk in the community is largely unexplored. We here investigated the involvement of rare genetic variants in SCA risk at the population level by studying the prevalence of 6 founder genetic variants present in the Dutch population (PLN-p.Arg14del, MYBPC3-p.Trp792fsX17, MYBPC3-p.Arg943X, MYBPC3-p.Pro955fsX95, PKP2-p.Arg79X, and the Chr7q36 idiopathic ventricular fibrillation risk haplotype) in a cohort of 1440 unselected Dutch SCA victims included in the Amsterdam Resuscitation Study (ARREST). The six studied founder mutations were found to be more prevalent (1.1%) in the ARREST SCA cohort compared with an ethnically and geographically matched set of controls (0.4%, n=1379; P<0.05) or a set of Dutch individuals drawn from the Genome of the Netherlands (GoNL) study (0%, n=500; P<0.02). This finding provides proof-of-concept for the notion that rare genetic variants contribute to some extent to SCA risk in the community. Show less

Non-alcoholic fatty liver disease (NAFLD) is a consequence of sedentary life style and high fat diets with an estimated prevalence of about 30% in western countries. It is associated with insulin resistance, obesity, glucose intolerance and drug toxicity. Additionally, polymorphisms within, e.g., APOC3, PNPLA3, NCAN, TM6SF2 and PPP1R3B, correlate with NAFLD. Several studies have already investigated later stages of the disease. This study explores the early steatosis stage of NAFLD with the aim of identifying molecular mechanisms underlying the etiology of NAFLD. We analyzed liver biopsies and serum samples from patients with high- and low-grade steatosis (also pre-disease states) employing transcriptomics, ELISA-based serum protein analyses and metabolomics. Here, we provide a detailed description of the various related datasets produced in the course of this study. These datasets may help other researchers find new clues for the etiology of NAFLD and the mechanisms underlying its progression to more severe disease states. Show less

Conazole fungicides are widely used in agriculture despite their suspected endocrine disrupting properties. In this study, the potential (anti-)androgenic effects of ten conazoles were assessed and mutually compared with existing data. Effects of cyproconazole (CYPRO), fluconazole (FLUC), flusilazole (FLUS), hexaconazole (HEXA), myconazole (MYC), penconazole (PEN), prochloraz (PRO), tebuconazole (TEBU), triadimefon (TRIA), and triticonazole (TRIT) were examined using murine Leydig (MA-10) cells and human T47D-ARE cells stably transfected with an androgen responsive element and a firefly luciferase reporter gene. Six conazoles caused a decrease in basal testosterone (T) secretion by MA-10 cells varying from 61% up to 12% compared to vehicle-treated control. T secretion was concentration-dependently inhibited after exposure of MA-10 cells to several concentrations of FLUS (IC Show less

Mutations in apolipoprotein A5 (APOA5) have been associated with hypertriglyceridemia in humans and mice. This has been attributed to a stimulating role for APOA5 in lipoprotein lipase-mediated triglyceride hydrolysis and hepatic clearance of lipoprotein remnant particles. However, because of the low APOA5 plasma abundance, we investigated an additional signaling role for APOA5 in high-fat diet (HFD)-induced obesity. Wild-type (WT) and Apoa5(-/-) mice fed a chow diet showed no difference in body weight or 24-h food intake (Apoa5(-/-), 4.5±0.6 g; WT, 4.2±0.5 g), while Apoa5(-/-) mice fed an HFD ate more in 24 h (Apoa5(-/-), 2.8±0.4 g; WT, 2.5±0.3 g, P<0.05) and became more obese than WT mice. Also, intravenous injection of APOA5-loaded VLDL-like particles lowered food intake (VLDL control, 0.26±0.04 g; VLDL+APOA5, 0.11±0.07 g, P<0.01). In addition, the HFD-induced hyperphagia of Apoa5(-/-) mice was prevented by adenovirus-mediated hepatic overexpression of APOA5. Finally, intracerebroventricular injection of APOA5 reduced food intake compared to injection of the same mouse with artificial cerebral spinal fluid (0.40±0.11 g; APOA5, 0.23±0.08 g, P<0.01). These data indicate that the increased HFD-induced obesity of Apoa5(-/-) mice as compared to WT mice is at least partly explained by hyperphagia and that APOA5 plays a role in the central regulation of food intake. Show less

Elevated cholesterol levels in children can be a risk factor for cardiovascular diseases in later life. In adults, it has been shown that blood lipid levels are strongly influenced by polymorphisms in the fatty acid desaturase (FADS) gene cluster in addition to nutritional and other exogenous and endogenous determinants. Our aim was to investigate whether lipid levels are determined by the FADS genotype already in children and whether this association interacts with dietary intake of n-3 fatty acids. The analysis was based on data of 2006 children from two German prospective birth cohort studies. Total cholesterol, HDL, LDL and triglycerides were measured at 10 years of age. Six single nucleotide polymorphisms (SNPs) of the FADS gene cluster were genotyped. Dietary n-3 fatty acid intake was assessed by food frequency questionnaire. Linear regression modeling was used to assess the association between lipid levels, n-3 fatty acid intake and FADS genotype. Individuals carrying the homozygous minor allele had lower levels of total cholesterol [means ratio (MR) ranging from 0.96 (p = 0.0093) to 0.98 (p = 0.2949), depending on SNPs] and LDL [MR between 0.94 (p = 0.0179) and 0.97 (p = 0.2963)] compared to homozygous major allele carriers. Carriers of the heterozygous allele showed lower HDL levels [β between -0.04 (p = 0.0074) to -0.01 (p = 0.3318)] and higher triglyceride levels [MR ranging from 1.06 (p = 0.0065) to 1.07 (p = 0.0028)] compared to homozygous major allele carriers. A higher n-3 PUFA intake was associated with higher concentrations of total cholesterol, LDL, HDL and lower triglyceride levels, but these associations did not interact with the FADS1 FADS2 genotype. Total cholesterol, HDL, LDL and triglyceride concentrations may be influenced by the FADS1 FADS2 genotype already in 10 year old children. Genetically determined blood lipid levels during childhood might differentially predispose individuals to the development of cardiovascular diseases later in life. Show less

The protective effect of breastfeeding (BF) on the development of asthma has been widely recognized, even if not all results have been consistent. Gene variants of the FADS gene cluster have a major impact on fatty acid composition in blood and in breast milk. Therefore, we evaluated the influence of the FADS1 FADS2 gene cluster polymorphisms on the association between BF and asthma. The analysis was based on data (N=2245) from two German prospective birth cohort studies. Information on asthma and BF during the first 6 months was collected using questionnaires completed by the parents. Logistic regression modelling was used to analyse the association between exclusive BF and ever having asthma stratified by genotype. In the stratified analyses, BF for 3 or 4 months after birth had a protective effect for heterozygous and homozygous carriers of the minor allele (adjusted odds ratio between 0.37 (95% CI: 0.18-0.80) and 0.42 (95% CI: 0.20-0.88). Interaction terms of BF with genotype were significant and ranged from -1.17 (P-value: 0.015) to -1.33 (0.0066). Moreover, heterozygous and homozygous carriers of the minor allele who were exclusively breastfed for 5 or 6 months after birth had a reduced risk of asthma [0.32 (0.18-0.57) to 0.47 (0.27-0.81)] in the stratified analyses. For individuals carrying the homozygous major allele, BF showed no significant effect on the development of asthma. The association between exclusive BF and asthma is modified by the genetic variants of FADS genotypes in children. Show less

In order to identify acute myeloid leukemia (AML) CD34(+)-specific gene expression profiles, mononuclear cells from AML patients (n=46) were sorted into CD34(+) and CD34(-) subfractions, and genome-wide expression analysis was performed using Illumina BeadChip Arrays. AML CD34(+) and CD34(-) gene expression was compared with a large group of normal CD34(+) bone marrow (BM) cells (n=31). Unsupervised hierarchical clustering analysis showed that CD34(+) AML samples belonged to a distinct cluster compared with normal BM and that in 61% of the cases the AML CD34(+) transcriptome did not cluster together with the paired CD34(-) transcriptome. The top 50 of AML CD34(+)-specific genes was selected by comparing the AML CD34(+) transcriptome with the AML CD34(-) and CD34(+) normal BM transcriptomes. Interestingly, for three of these genes, that is, ankyrin repeat domain 28 (ANKRD28), guanine nucleotide binding protein, alpha 15 (GNA15) and UDP-glucose pyrophosphorylase 2 (UGP2), a high transcript level was associated with a significant poorer overall survival (OS) in two independent cohorts (n=163 and n=218) of normal karyotype AML. Importantly, the prognostic value of the continuous transcript levels of ANKRD28 (OS hazard ratio (HR): 1.32, P=0.008), GNA15 (OS HR: 1.22, P=0.033) and UGP2 (OS HR: 1.86, P=0.009) was shown to be independent from the well-known risk factors FLT3-ITD, NPM1c(+) and CEBPA mutation status. Show less

The association between dietary fatty acid intake and the development of atopic diseases has been inconsistent. This could be due to inter-individual genetic differences in fatty acid metabolism. The aim of the current study was to assess the influence of FADS1 FADS2 gene cluster polymorphisms on the association between dietary fatty acid intake and atopic diseases and allergic sensitization in 10-year-old children. The analysis was based on data from two German prospective birth cohort studies. Data on margarine and fatty acid intake were collected using a food frequency questionnaire. Information on atopic diseases was collected using a questionnaire completed by the parents. Specific IgE against common food and inhalant allergens were measured. Six variants of the FADS1 FADS2 gene cluster (rs174545, rs174546, rs174556, rs174561, rs174575 and rs3834458) were tested. Logistic regression modelling, adjusted for gender, age, maternal education level and study centre, was used to analyse the association between fatty acid intake and atopic diseases stratified by genotype. No significant association was found between the six FADS single nucleotide polymorphisms (SNPs) and allergic diseases or atopic sensitization. The total n-3/total n-6 ratio was positive associated with an increased risk of hayfever in homozygous major allele carriers ranging from an adjusted odds ratios of 1.25 (95%-CI: 1.00-1.57) to 1.31 (95%-CI: 1.01-1.69) across the six tested SNPs although this association was not significant anymore after correcting for multiple testing. Daily margarine intake was significantly associated with asthma [1.17 (1.03-1.34) to 1.22 (1.06-1.40)] in individuals carrying the homozygous major allele. This association was also significant after correcting for multiple testing. The association between dietary intake of fatty acids and allergic diseases might be modulated by FADS gene variants in children. Show less

Essential tremor (ET) and Parkinson's disease (PD) are the most common movement disorders and show clinical, genetic, and pathophysiological overlap. Single-nucleotide polymorphisms (SNPs) in the leucine-rich repeat (LRR) and immunoglobulin (Ig) domain-containing, Nogo receptor-interacting protein gene (LINGO1) are associated with ET. LINGO1 is overexpressed in the substantia nigra (SN) of PD patients and inhibition of LINGO1 confers neuroprotection in a rodent model of PD. In this study we test the hypothesis whether SNPs in the LINGO1 gene that are associated with ET are also associated with PD. Three large German case-control samples from Kiel, Lübeck, and Tübingen (total: 1,798 cases and 1,482 controls) were genotyped for the three LINGO1 SNPs associated with ET. Association was assessed using allele- and genotype-based tests in each of the three samples separately, in the combined sample, and in subsets of patients with early-onset PD (<50 years) and of patients with a positive family history of PD. Neither of the three samples alone nor the combined sample showed evidence for association between LINGO1 SNPs and PD. The allele-based test showed a trend toward nominal association for all three SNPs in the Kiel sample. The subsets with early-onset PD or a positive family history did also not reveal evidence for association. SNPs in the LINGO1 gene associated with ET could not be shown to be associated with PD in our study population, despite a postulated overlap between both diseases. Show less

We conducted dense linkage disequilibrium (LD) mapping of a series of 25 genes putatively involved in lipid metabolism in 1567 dementia cases [including 1270 with Alzheimer disease (AD)] and 2203 Swedish controls. Across a total of 448 tested genetic markers, the strongest evidence of association was as anticipated for APOE (rs429358 at P approximately 10(-72)) followed by a previously reported association of ABCA1 (rs2230805 at P approximately 10(-8)). In the present study, we report two additional markers near the SREBF1 locus on chromosome 17p that were also significant after multiple testing correction (best P = 3.1 x 10(-6) for marker rs3183702). There was no convincing evidence of association for remaining genes, including candidates highlighted from recent genome-wide association studies of plasma lipids (CELSR2/PSRC1/SORT1, MLXIPL, PCSK9, GALNT2 and GCKR). The associated markers near SREBF1 reside in a large LD block, extending more than 400 kb across seven candidate genes. Secondary analyses of gene expression levels of candidates spanning the LD region together with an investigation of gene network context highlighted two possible susceptibility genes including ATPAF2 and TOM1L2. Several markers in strong LD (r(2) > 0.7) with rs3183702 were found to be significantly associated with AD risk in recent genome-wide association studies with similar effect sizes, providing independent support of the current findings. Show less

We investigated the presence of a clinical diagnosis of hypertrophic cardiomyopathy (HCM) and of risk factors for sudden cardiac death (SCD) at the first cardiological evaluation after predictive genetic testing in asymptomatic carriers of an MYBPC3 gene mutation. Two hundred and thirty-five mutation carriers were cardiologically evaluated on the presence of HCM and risk factors. A clinical diagnosis of HCM was made in 53 carriers (22.6%). Disease penetrance at 65 years was incomplete for all types of MYBPC3 gene mutations. Women were affected less often than men (15 and 32% respectively, P = 0.003) and disease penetrance was lower in females than in males (13 and 30% at 50 years, respectively, P = 0.024). One risk factor was present in 87 carriers and 9 had two or more risk factors. Twenty-five carriers (11%) with one or more risk factors and manifest HCM could be at risk for SCD. At first cardiological evaluation almost one-quarter of asymptomatic carriers was diagnosed with HCM. Risk factors for SCD were frequently present and 11% of carriers could be at risk for SCD. Predictive genetic testing in HCM families and frequent cardiological evaluation on the presence of HCM and risk factors for SCD are justified until advanced age. Show less

The liver X receptors (LXR) α and β regulate lipid and carbohydrate homeostasis and inflammation. Lxrβ⁻/⁻ mice are glucose intolerant and at the same time lean. We aimed to assess the associations between single nucleotide polymorphisms (SNPs) in LXRβ and risk of type 2 diabetes mellitus (T2DM), obesity and related traits in 3 separate cohort studies. Twenty LXRβ SNPs were identified by sequencing and genotyped in the HUNT2 adult nested case-control study for T2DM (n = 835 cases/1986 controls). Five tag-SNPs (rs17373080, rs2695121, rs56151148, rs2303044 and rs3219281), covering 99.3% of the entire common genetic variability of the LXRβ gene were identified and genotyped in the French MONICA adult study (n = 2318) and the European adolescent HELENA cross-sectional study (n = 1144). In silico and in vitro functionality studies were performed. We identified suggestive or significant associations between rs17373080 and the risk of (i) T2DM in HUNT2 (OR = 0.82, p = 0.03), (ii) obesity in MONICA (OR = 1.26, p = 0.05) and (iii) overweight/obesity in HELENA (OR = 1.59, p = 0.002). An intron 4 SNP (rs28514894, a perfect proxy for rs17373080) could potentially create binding sites for hepatic nuclear factor 4 alpha (HNF4α) and nuclear factor 1 (NF1). The C allele of rs28514894 was associated with ~1.25-fold higher human LXRβ basal promoter activity in vitro. However, no differences between alleles in terms of DNA binding and reporter gene transactivation by HNF4α or NF1 were observed. Our results suggest that rs17373080 in LXRβ is associated with T2DM and obesity, maybe via altered LXRβ expression. Show less

Chromatin states have to be faithfully duplicated during DNA replication to maintain cell identity. It is unclear whether or how ATP-dependent chromatin-remodelling factors are involved in this process. Here we provide evidence that the Williams syndrome transcription factor (WSTF) is targeted to replication foci through direct interaction with the DNA clamp PCNA, an important coordinator of DNA and chromatin replication. WSTF, in turn, recruits imitation switch (ISWI)-type nucleosome-remodelling factor SNF2H to replication sites. These findings reveal a novel recruitment mechanism for ATP-dependent chromatin-remodelling factors that is fundamentally different from the previously documented targeting by sequence-specific transcriptional regulators. RNA-interference-mediated depletion of WSTF or SNF2H causes a compaction of newly replicated chromatin and increases the amount of heterochromatin markers, including HP1beta. This increase in the amount of HP1beta protein is mediated by progression through S phase and is not the result of an increase in HP1beta mRNA levels. We propose that the WSTF-ISWI complex has a role in the maintenance of chromatin structures during DNA replication. Show less

In searching for a tumor suppressor gene in the 3p21.3 region, we isolated two genes, RBM5 and RBM6. Sequence analysis indicated that these genes share similarity. RBM5 and-to a lesser extent-RBM6 also have similarity to DXS8237E at Xp11.3-11.23, which maps less than 20 kb upstream of UBE1. A homologue of UBE1, UBE1L, is located at 3p21. 3. FISH analysis showed that the distance between UBE1L and RBM5 in 3p21.3 is about 265 kb. DXS8237E and UBE1 on the X chromosome have the same orientation, whereas on chromosome 3 the orientation of RBM5 and that of RBM6 are opposite to the orientation of UBE1L. Presumably, part of the Xp11.3-11.23 region has duplicated to chromosome 3. Part of this region on chromosome 3 may subsequently have duplicated again within the same chromosomal region. Inversion at some stage of the evolution of the human genome would explain the change in orientation of the genes on chromosome 3 compared with that of the genes on the X chromosome. Show less

In the search for a tumour suppressor gene in the 3p21.3 region we isolated two genes, RBM5 and RBM6. Gene RBM5 maps to the region which is homozygously deleted in the small cell lung cancer cell line GLC20; RBM6 crosses the telomeric breakpoint of this deletion. Sequence comparison revealed that at the amino acid level both genes show 30% identity. They contain two zinc finger motifs, a bipartite nuclear signal and two RNA binding motifs, suggesting that the proteins for which RBM5 and RBM6 are coding have a DNA/RNA binding function and are located in the nucleus. Northern and Southern analysis did not reveal any abnormalities. By SSCP analysis of 16 lung cancer cell lines we found only in RBM5 a single presumably neutral mutation. By RT-PCR we demonstrated the existence of two alternative splice variants of RBM6, one including and one excluding exon 5, in both normal lung tissue and lung cancer cell lines. Exclusion of exon 5 results in a frameshift which would cause a truncated protein of 520 amino acids instead of 1123 amino acids. In normal lung tissue, the relative amount of the shorter transcript was much greater than that in the lung tumour cell lines, which raises the question whether some tumour suppressor function may be attributed to the derived shorter protein. Show less