This thesis explores biochemical and genetical changes associated with migraine and cluster headache. This research aims to increase knowledge of the pathophysiology and signaling pathways involved... Show moreThis thesis explores biochemical and genetical changes associated with migraine and cluster headache. This research aims to increase knowledge of the pathophysiology and signaling pathways involved in migraine and cluster headache, thereby identifying new targets for treatment. Uncovering the biological mechanisms on how patients differ from those without disease leads to a better understanding of the pathophysiology of primary headache disorders. The biological systems in our body are related to each other, and are based on the genomic blueprint and lead via epigenetics, transcription and translation to proteins and biomolecules. The first part of the dissertation focuses on the examination of biomolecules in body fluids (blood and cerebrospinal fluid) in migraineurs. Several studies showed that biomolecule concentrations differed between people with and without migraine for lipids, amino acids and metabolites of glucose metabolism. These results indicate a general disruption of the metabolic profile in migraineurs. For other substances, no differences were found. The second part of the thesis looked at the genetic blueprint of various headache disorders. There a genetic difference between people with migraine and people without migraine was found. In addition, a genetic difference between people with and without cluster headache was found. Show less
Guimaraes, T.A.C. de; Georgiou, M.; Robson, A.G.; Fujinami, K.; Vincent, A.; Nasser, F.; ... ; Michaelides, M. 2023
Background/aims To investigate genotype-phenotype associations in patients with KCNV2 retinopathy.Methods Review of clinical notes, best-corrected visual acuity (BCVA), molecular variants,... Show moreBackground/aims To investigate genotype-phenotype associations in patients with KCNV2 retinopathy.Methods Review of clinical notes, best-corrected visual acuity (BCVA), molecular variants, electroretinography (ERG) and retinal imaging. Subjects were grouped according to the combination of KCNV2 variants-two loss-of-function (TLOF), two missense (TM) or one of each (MLOF)-and parameters were compared.Results Ninety-two patients were included. The mean age of onset (mean +/- SD) in TLOF (n=55), TM (n=23) and MLOF (n=14) groups was 3.51 +/- 0.58, 4.07 +/- 2.76 and 5.54 +/- 3.38 years, respectively. The mean LogMAR BCVA ( +/- SD) at baseline in TLOF, TM and MLOF groups was 0.89 +/- 0.25, 0.67 +/- 0.38 and 0.81 +/- 0.35 for right, and 0.88 +/- 0.26, 0.69 +/- 0.33 and 0.78 +/- 0.33 for left eyes, respectively. The difference in BCVA between groups at baseline was significant in right (p=0.03) and left eyes (p=0.035). Mean outer nuclear layer thickness ( +/- SD) at baseline in TLOF, MLOF and TM groups was 37.07 +/- 15.20 mu m, 40.67 +/- 12.53 and 40.38 +/- 18.67, respectively, which was not significantly different (p=0.85). The mean ellipsoid zone width (EZW) loss ( +/- SD) was 2051 mu m ( +/- 1318) for patients in the TLOF, and 1314 mu m ( +/- 965) for MLOF. Only one patient in the TM group had EZW loss at presentation. There was considerable overlap in ERG findings, although the largest DA 10 ERG b-waves were associated with TLOF and the smallest with TM variants.Conclusions Patients with missense alterations had better BCVA and greater structural integrity. This is important for patient prognostication and counselling, as well as stratification for future gene therapy trials. Show less
Bos, T.A.; Piers, S.R.D.; Wessels, M.W.; Houweling, A.C.; Bökenkamp, R.; Bootsma, M.; ... ; European Reference Network Rare 2023
BackgroundThe arrhythmogenic cardiomyopathy (ACM) phenotype, with life-threatening ventricular arrhythmias and heart failure, varies according to genetic aetiology. We aimed to characterise the... Show moreBackgroundThe arrhythmogenic cardiomyopathy (ACM) phenotype, with life-threatening ventricular arrhythmias and heart failure, varies according to genetic aetiology. We aimed to characterise the phenotype associated with the variant c.1211dup (p.Val406Serfs*4) in the plakophilin-2 gene (PKP2) and compare it with previously reported Dutch PKP2 founder variants.MethodsClinical data were collected retrospectively from medical records of 106 PKP2 c.1211dup heterozygous carriers. Using data from the Netherlands ACM Registry, c.1211dup was compared with 3 other truncating PKP2 variants (c.235C > T (p.Arg79*), c.397C > T (p.Gln133*) and c.2489+1G > A (p.?)).ResultsOf the 106 carriers, 47 (44%) were diagnosed with ACM, at a mean age of 41 years. By the end of follow-up, 29 (27%) had experienced sustained ventricular arrhythmias and 12 (11%) had developed heart failure, with male carriers showing significantly higher risks than females on these endpoints (p < 0.05). Based on available cardiac magnetic resonance imaging and echocardiographic data, 46% of the carriers showed either right ventricular dilatation and/or dysfunction, whereas a substantial minority (37%) had some form of left ventricular involvement. Both geographical distribution of carriers and haplotype analysis suggested PKP2 c.1211dup to be a founder variant originating from the South-Western coast of the Netherlands. Finally, a Cox proportional hazards model suggested significant differences in ventricular arrhythmia-free survival between 4 PKP2 founder variants, including c.1211dup.ConclusionsThe PKP2 c.1211dup variant is a Dutch founder variant associated with a typical right-dominant ACM phenotype, but also left ventricular involvement, and a possibly more severe phenotype than other Dutch PKP2 founder variants. Show less
Aims/hypothesis Characterisation of genetic variation that influences the response to glucose-lowering medications is instrumental to precision medicine for treatment of type 2 diabetes. The Study... Show moreAims/hypothesis Characterisation of genetic variation that influences the response to glucose-lowering medications is instrumental to precision medicine for treatment of type 2 diabetes. The Study to Understand the Genetics of the Acute Response to Metformin and Glipizide in Humans (SUGAR-MGH) examined the acute response to metformin and glipizide in order to identify new pharmacogenetic associations for the response to common glucose-lowering medications in individuals at risk of type 2 diabetes.Methods One thousand participants at risk for type 2 diabetes from diverse ancestries underwent sequential glipizide and metformin challenges. A genome-wide association study was performed using the Illumina Multi-Ethnic Genotyping Array. Imputation was performed with the TOPMed reference panel. Multiple linear regression using an additive model tested for association between genetic variants and primary endpoints of drug response. In a more focused analysis, we evaluated the influence of 804 unique type 2 diabetes- and glycaemic trait-associated variants on SUGAR-MGH outcomes and performed colocalisation analyses to identify shared genetic signals.Results Five genome-wide significant variants were associated with metformin or glipizide response. The strongest association was between an African ancestry-specific variant (minor allele frequency [MAF(Afr)]=0.0283) at rs149403252 and lower fasting glucose at Visit 2 following metformin (p=1.9x10(-9)); carriers were found to have a 0.94 mmol/l larger decrease in fasting glucose. rs111770298, another African ancestry-specific variant (MAF(Afr)=0.0536), was associated with a reduced response to metformin (p=2.4x10(-8)), where carriers had a 0.29 mmol/l increase in fasting glucose compared with non-carriers, who experienced a 0.15 mmol/l decrease. This finding was validated in the Diabetes Prevention Program, where rs111770298 was associated with a worse glycaemic response to metformin: heterozygous carriers had an increase in HbA(1c) of 0.08% and non-carriers had an HbA(1c) increase of 0.01% after 1 year of treatment (p=3.3x10(-3)). We also identified associations between type 2 diabetes-associated variants and glycaemic response, including the type 2 diabetes-protective C allele of rs703972 near ZMIZ1 and increased levels of active glucagon-like peptide 1 (GLP-1) (p=1.6x10(-5)), supporting the role of alterations in incretin levels in type 2 diabetes pathophysiology.Conclusions/interpretation We present a well-phenotyped, densely genotyped, multi-ancestry resource to study gene-drug interactions, uncover novel variation associated with response to common glucose-lowering medications and provide insight into mechanisms of action of type 2 diabetes-related variation. Show less
Kapteijn, M.Y.; Kaptein, F.H.J.; Stals, M.A.M.; Klaase, E.E.; Eijk, R. van; Ruano, D.; ... ; Garcia-Ortiz, I. 2023
Background and objectives: Patients with glioblastoma have a high risk of developing venous thromboembolism (VTE). However, the role of underlying genetic risk factors remains largely unknown.... Show moreBackground and objectives: Patients with glioblastoma have a high risk of developing venous thromboembolism (VTE). However, the role of underlying genetic risk factors remains largely unknown. Therefore, the aim of this study was to discover whether genetic aberrations in glioblastoma associate with VTE risk.Methods: In this cohort study, all consecutive patients diagnosed with glioblastoma in two Dutch hospitals be-tween February 2017 and August 2020 were included. Targeted DNA next-generation sequencing of all glio-blastomas was performed for diagnostic purposes and included mutational status of the genes ATRX, BRAF, CIC, FUBP1, H3F3A, IDH1, IDH2, PIK3CA, PTEN and TP53 and amplification/gain or deletion of BRAF, CDKN2A, EGFR, NOTCH1 and PTEN. The primary outcome was VTE within three months before glioblastoma diagnosis until two years after. Cumulative incidences were determined using competing risk analysis adjusting for mor-tality. Univariable Cox regression analysis was performed to determine hazard ratios.Results: From 324 patients with glioblastoma, 25 were diagnosed with VTE. Patients with a CDKN2A deletion had a 12-month adjusted cumulative incidence of VTE of 12.5 % (95%CI: 7.3-19.3) compared with 5.4 % (95%CI: 2.6-9.6) in patients with CDKN2A wildtype (p = 0.020), corresponding to a HR of 2.53 (95%CI: 1.12-5.73, p = 0.026). No significant associations were found between any of the other investigated genes and VTE.Conclusion: This study suggests a potential role for CDKN2A deletion in glioblastoma-related VTE. Therefore, once independently validated, CDKN2A mutational status may be a promising predictor to identify glioblastoma patients at high risk for VTE, who may benefit from thromboprophylaxis. Show less
This thesis describes the genetic and prokaryotic diversity of giant barrel sponges. Although it was originally believed that the giant barrel sponges in the AtlanticOcean and the Indo-Pacific... Show moreThis thesis describes the genetic and prokaryotic diversity of giant barrel sponges. Although it was originally believed that the giant barrel sponges in the AtlanticOcean and the Indo-Pacific Ocean were two different species, our analyses showed thatthere are several species in both ocean basins. Even more remarkable, is that each species is most closely related to a species in the other ocean basin. According to our analysis, there are threegiant barrel sponge species in the Atlantic Ocean, and, at least, six in the Indo-Pacific Ocean. Sponges house a large and diverse community of microorganisms. It is generally believed thatthese microorganisms play a central role in the physiological processes in the host. It appears that the region in which a giant barrel sponge occursmainly determines the composition of their microbial community. However, if you lookat a smaller scale within a region, for example within one reef or around an island suchas Curaçao, it appears that not only is the geographical location important, but the hostspecies to which an individual belongs also plays an important role. Show less
Streptomyces are multicellular, Gram-positive bacteria in the phylum of actinobacteria which produce a high amount of bioactive natural products of which the expression is tightly coordinated with... Show moreStreptomyces are multicellular, Gram-positive bacteria in the phylum of actinobacteria which produce a high amount of bioactive natural products of which the expression is tightly coordinated with the life cycle. This thesis shows the identification of S. roseifaciens, a novel species with an uncommon, verticillate spore morphology and a unique household of SsgA-like proteins. Analyses of the peptidoglycan composition show that S. coelicolor show a pattern of 3-3 cross-linking befitting a tip-growing organism and change in composition between vegetative mycelium and spores. Kitasatosporae carry meso-DAP in the peptidoglycan of vegetative mycelium and LL-DAP in the peptidoglycan of spores. In line with this difference, the peptidoglycan architecture of these two growth stages undergoes such radical changes that they would seem to be from different species. S. coelicolor is naturally vancomycin resistant, but the addition of D-alanine and disruption in a single gene increases vancomycin sensitivity by a thousandfold. A knockout mutant of the alanine racemase, alr, requires exogenous addition of D-alanine. The Alr crystal structure of S. coelicolor and the D-cycloserine producer S. lavendulae were compared as to look for possible mechanisms for D-cycloserine resistance. Show less
A large part of the human genome consists of repetitive DNA. In this thesis two human diseases have been studied in which deregulation of repetitive DNA is a central feature: facioscapulohumeral... Show moreA large part of the human genome consists of repetitive DNA. In this thesis two human diseases have been studied in which deregulation of repetitive DNA is a central feature: facioscapulohumeral muscular dystrophy (FSHD) and immunodeficiency, centromere instability and facial anomalies (ICF) syndrome. FSHD is caused by the misexression of the transcription factor DUX4 in skeletal muscle. DUX4 is encoded in the D4Z4 repeat array and is silenced in healthy somatic tissues. In this thesis, several aspects of the epigenetic deregulation of DUX4 in FSHD are described. We have analysed possible correlations between disease severity and epigenetic organization of the D4Z4 repeat. Next we showed that cellular ageing results in deregulation of genomic regions like D4Z4. Moreover, we show that SMCHD1 is the main epigenetic repressor of DUX4 in somatic cells. We next showed that DUX4 misexpression results in the activation of an FSHD candidate gene, FRG2. Finally, we report the generation of a transgenic mouse model for FSHD. The disease mechanism of ICF syndrome remains to be elucidated. However, in this thesis we identify two new ICF disease genes. We highlight a role for all four known ICF genes in repressing repetitive DNA, suggesting functional convergence of these genes. Show less
Jasmonates (JAs) are crucial plant signaling molecules that regulate defense responses against wounding, insects and necrotrophic pathogens. The biosynthesis of JAs is regulated by a positive... Show moreJasmonates (JAs) are crucial plant signaling molecules that regulate defense responses against wounding, insects and necrotrophic pathogens. The biosynthesis of JAs is regulated by a positive feedback loop. This thesis reveals the transcriptional regulatory mechanism behind this positive feedback loop in Arabidopsis. The studies show that the bHLH-domain transcription factors MYC2, MYC3 and MYC4 positively regulate most JAs biosynthesis genes directly and by controlling the expression of ORA47 gene, encoding a regulator of JAs biosynthesis. Show less
Advances in technology have turned modern biology into a data-intensive enterprise. The advent of high-output technologies like Microarrays and Next-generation sequencing technologies has resulted... Show moreAdvances in technology have turned modern biology into a data-intensive enterprise. The advent of high-output technologies like Microarrays and Next-generation sequencing technologies has resulted in researchers grappling not just with huge volumes but also multiple types of data. While generation and storage of high-quality data are an important research focus, it is increasingly recognized that translating data into actionable information and insight is a critical research challenge. To infer reliable conclusions from the data, it is often necessary to integrate large amounts of heterogeneous data with different formats and semantics. Given the breadth and volume of data involved, this goal is best achieved through automated methods and tools for data integration and workflow management. This thesis presents automated strategies that combine bioinformatics and statistical methods to identify novel biomarkers in high-throughput OMICs datasets pertaining to the metabolic syndrome and to gain mechanistic insight into the underlying biological processes. An underlying theme in this thesis is data-driven approaches that generate plausible hypothesis which is followed by experimental verification. Show less
The ultimate goal of translational colon and rectal cancer research is to turn these types of cancer into curable or manageable chronic diseases. The approach to achieve this is to enable... Show moreThe ultimate goal of translational colon and rectal cancer research is to turn these types of cancer into curable or manageable chronic diseases. The approach to achieve this is to enable clinicians to make (adjuvant) treatment decisions, based on the individual patient characteristics and individual characteristics of a patient__s tumor. Identification of new prognostic and predictive biomarkers, based on the biology of individual tumor characteristics, is therefore warranted to further refine the current TNM classification. This thesis describes the use of molecular techniques for the identification of prognostic biomarkers for clinical outcome in (sporadic) colon and rectal cancer. We here present compelling candidate biomarker combinations for validation in further studies. Retrospective and prospective validation of these prognostic biomarker combinations in international and independent patient series is therefore the crucial next step. Additionally, the presented studies stress the importance of -1- combining biomarkers based on tumor biology, -2- integrative analysis of cancer hallmark related processes at all different cellular regulatory levels (genetics, epigenetics and protein level), -3- assessment of tissue specificity between colon and rectal tumors, and -4- studying age-related effects in future colorectal cancer research. Show less
Rheumatoid arthritis is a chronic auto-immune disorder, of which persistent synovitis, bone erosions and auto-antibody formation are characteristic features. Although the etiology of the disease... Show moreRheumatoid arthritis is a chronic auto-immune disorder, of which persistent synovitis, bone erosions and auto-antibody formation are characteristic features. Although the etiology of the disease remains largely unknown, it is established that genetic risk factors play a pivotal role in disease pathology. Both family and twin studies have shown that the genetic contribution to the disease can be estimated around 50%. In the current thesis the genetic contribution of non-HLA genes to RA susceptibility was further investigated and the functional relevance of these loci was explored. The studies described were able to establish several previously identified risk factors in a statistical robust manner. Also novel genetic risk factors that are associated with RA susceptibility could be identified, as well as risk factors that are conferred to specific subgroups of the disease. Show less
Juvenile idiopathic arthritis (JIA) is a non-common disease in children that can persist into adulthood. JIA is considered to be an auto-immune disease. Genetic factors play a role in the... Show moreJuvenile idiopathic arthritis (JIA) is a non-common disease in children that can persist into adulthood. JIA is considered to be an auto-immune disease. Genetic factors play a role in the pathogenesis. In a new cohort of JIA patients from North-West European descent genetic candidate gene association studies have been performed. In this cohort we have discovered new associations with the susceptibility of JIA and the genes/loci TRAF1/C5, 4q27, CD226 and CD28. These genes have already been associated with other auto-immune diseases and might be part of a shared common auto-immune susceptibility. Also genetic association with the course of disease has been studied, revealing an association of VTCN1 and the severity of JIA defined by the percentage of active disease in the first two years. VTCN1 encodes B7-H4 that is involved in the co-stimulation of T-cells and inhibits the immune-response. Until the precise role of VTCN1 will be clarified, the genetic association might be of use in predicting the course of disease and might be a lead point for new treatment. Show less
Primary vascular tumors of bone are a heterogeneous group. Numerous terms have been introduced as well as different classification systems. However, so far none of them have been generally accepted... Show morePrimary vascular tumors of bone are a heterogeneous group. Numerous terms have been introduced as well as different classification systems. However, so far none of them have been generally accepted.Therefor, there is a need for more specific morphological, immunohistochemical and molecular tools to support the classification of different vascular tumors of bone. In this thesis, we attempt to delineate the high-grade malignant vascular tumors of bone based on histomorphological criteria, protein expression profile based on a large panel of oncogenes, tumor-suppressor genes and signaling molecules, and molecular data. Moreover, we compared our dataset with a small groups of angiosarcoma of soft tissue in order to see whether these are truly different tumors or whether they should be regarded as one entity with a different localization. Finally, we question whether the rare vascular tumor previously designated as "haemangiopericytoma of bone" is a true entity or should rather be regarded as a growth pattern. Show less
Although much research effort has been put into the development of new antidepressant drugs, the process of developing a drug often fails at the stage of large randomized controlled trials (RCTs)... Show moreAlthough much research effort has been put into the development of new antidepressant drugs, the process of developing a drug often fails at the stage of large randomized controlled trials (RCTs) in which an initially promising compound appears to lack efficacy after all. Several experimental medicine models have been proposed as preclinical tools in order to predict drug efficacy before the stage large RCTs. Among the various experimental medicine models, the cognitive neuropsychological model has been proposed as a tool to predict the efficacy of antidepressant drug even before the stage of large scale and expensive RCTs. We applied the cognitive neuropsychological model of drug action to test antidepressant effects of a novel compound (ARA290) and a well-known compound (L-tryptophan). We further investigated the model by tapping into HPA-axis reactivity and social decision making as additional outcomes, and investigated their interaction with a genetic marker. Show less
Aim of this thesis was to investigate pharmacogenetic effects on response to statin treatment and the genetics of lipid metabolism and cardiovascular disease. In chapter 4 the first results of the... Show moreAim of this thesis was to investigate pharmacogenetic effects on response to statin treatment and the genetics of lipid metabolism and cardiovascular disease. In chapter 4 the first results of the Genomic investigation of Statin Therapy (GIST) consortium are presented. We identified and validated two new GWAS loci to be associated with LDL-cholesterol response after statin treatment. In addition, we confirmed two previous identified loci. In chapter 5 we showed that we were not able to identify any loci associated with differential event reduction after statin therapy within the PROSPER study. The results presented in chapter 8 show that even at old age a genetic predisposition to high LDL-cholesterol is a risk factor for mortality. The results of this thesis show that currently the possibilities to personalize statin treatment based on genetic variants is limited. New research methods will hopefully give new opportunities to improve cardiovascular disease treatment and give more insight into the biological mechanisms of statin treatment. Show less
The aim of this thesis was to identify novel lifespan regulating loci that influence human longevity and population mortality. To this end, we performed two genome-wide association studies, one of... Show moreThe aim of this thesis was to identify novel lifespan regulating loci that influence human longevity and population mortality. To this end, we performed two genome-wide association studies, one of long-lived individuals from the family-based Leiden Longevity Study (LLS) and an extended one of long-lived individuals from multiple cohorts of European descent. Using the latter, we identified two genome-wide significant loci, the TOMM40/APOE/APOC1 locus and an intergenic locus on chromosome 5q33.3. In addition, our gene set analysis with the LLS data showed that genetic variation in genes involved in the insulin/IGF-1 signaling and telomere maintenance pathways is associated with human longevity. Since our genetic studies identified a limited number of longevity loci, we additionally examined whether leukocyte telomere length (LTL) could be used as a biomarker of healthy aging. We showed that LTL meets three of the four criteria for a biomarker of healthy aging in the LLS, i.e., LTL changes with chronological age and is associated with health, in this case immune-related parameters, and prospective mortality. To identify novel longevity loci, future research may benefit from a better definition of the healthy aging phenotype, combining study designs, and the use of novel methods and technologies, such as next-generation sequencing. Show less
Rheumatoid Arthritis (RA) is a chronic autoimmune disorder that affects approximately 0.5-1% of the population. RA leads to inflammation of the joints and leads to irreversible destruction of... Show moreRheumatoid Arthritis (RA) is a chronic autoimmune disorder that affects approximately 0.5-1% of the population. RA leads to inflammation of the joints and leads to irreversible destruction of joints with subsequently to significant morbidity, disability for patients. Remarkably the amount of joint destruction differs substantially between patients. Currently medication mainly aims at diminishing inflammation. Because joint destruction seems to develop even when the inflammation level is low, since RA is still not curable and finally because joint destruction is irreversible, joint destruction becomes an increasingly important feature in patients with RA. In this dissertation, different aspects of joint destruction in RA were investigated. To highlight the most important findings: first of all the heritability of joint destruction was demonstrated. In addition several genes were further studied. Two genetic findings were of most interest: IL2RA was associated with joint destruction. Since there is already medication available that aims at IL2RA, this finding creates a new treatment option for the nearby future. More intriguingly, SPAG16, an thus far with sperm association gene, appears to be relevant in joint destruction in RA as well. This put a totally new light on the gene. Naturally, most of the newly discovered associations will need further research before they can be applied in clinical practice. Show less
Part I of this thesis starts with a description of the Leiden Early Arthritis Clinic, followed by chapters on predicting the progression from Undifferentiated Arthritis to Rheumatoid Arthritis (RA)... Show morePart I of this thesis starts with a description of the Leiden Early Arthritis Clinic, followed by chapters on predicting the progression from Undifferentiated Arthritis to Rheumatoid Arthritis (RA) and predicting the severity of RA by clinical information available early in the disease stage. In part II of this thesis, several studies to genetic factors underlying the differences in the severity of joint destruction, are presented. Most importantly, we report interesting associations between SNPs in the genes encoding Wnt-signalling proteins and the MMP-9 gene and progression of joint destruction. Part III of this thesis is devoted to ACPA-negative RA. Evidence is emerging that we should consider this a distinct pathofysiological entity from ACPA-positive RA. We also report the results of a Genome Wide Association Study (GWAS) to the radiographic progression of RA. In part IV of this thesis, we describe two studies to non-genetic factors that could influence the severity of RA. We did not find any clear seasonal differences for the season of RA onset. We also conclude that although smoking influences the long-term outcome of RA, the effect of smoking is not independent of ACPA-status. Show less
In this thesis I describe the developmental role of the Y-family polymerases Pol Eta, Pol Kappa and Rev1 in protection against exogenous and endogenous damage in C. elegans. Furthermore I identify... Show moreIn this thesis I describe the developmental role of the Y-family polymerases Pol Eta, Pol Kappa and Rev1 in protection against exogenous and endogenous damage in C. elegans. Furthermore I identify a new role for the A-family Polymerase Pol Theta in repair of replication-associated breaks. Show less
