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"Van Camp, Guy"
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Mutations in Splicing Factor Genes Are a Major Cause of Autosomal Dominant Retinitis Pigmentosa in Belgian Families
2017
Autosomal dominant retinitis pigmentosa (adRP) is characterized by an extensive genetic heterogeneity, implicating 27 genes, which account for 50 to 70% of cases. Here 86 Belgian probands with possible adRP underwent genetic testing to unravel the molecular basis and to assess the contribution of the genes underlying their condition.
Mutation detection methods evolved over the past ten years, including mutation specific methods (APEX chip analysis), linkage analysis, gene panel analysis (Sanger sequencing, targeted next-generation sequencing or whole exome sequencing), high-resolution copy number screening (customized microarray-based comparative genomic hybridization). Identified variants were classified following American College of Medical Genetics and Genomics (ACMG) recommendations.
Molecular genetic screening revealed mutations in 48/86 cases (56%). In total, 17 novel pathogenic mutations were identified: four missense mutations in RHO, five frameshift mutations in RP1, six mutations in genes encoding spliceosome components (SNRNP200, PRPF8, and PRPF31), one frameshift mutation in PRPH2, and one frameshift mutation in TOPORS. The proportion of RHO mutations in our cohort (14%) is higher than reported in a French adRP population (10.3%), but lower than reported elsewhere (16.5-30%). The prevalence of RP1 mutations (10.5%) is comparable to other populations (3.5%-10%). The mutation frequency in genes encoding splicing factors is unexpectedly high (altogether 19.8%), with PRPF31 the second most prevalent mutated gene (10.5%). PRPH2 mutations were found in 4.7% of the Belgian cohort. Two families (2.3%) have the recurrent NR2E3 mutation p.(Gly56Arg). The prevalence of the recurrent PROM1 mutation p.(Arg373Cys) was higher than anticipated (3.5%).
Overall, we identified mutations in 48 of 86 Belgian adRP cases (56%), with the highest prevalence in RHO (14%), RP1 (10.5%) and PRPF31 (10.5%). Finally, we expanded the molecular spectrum of PRPH2, PRPF8, RHO, RP1, SNRNP200, and TOPORS-associated adRP by the identification of 17 novel mutations.
Journal Article
Risk of Cardiac Valve Regurgitation with Dopamine Agonist use in Parkinson’s Disease and Hyperprolactinaemia
by
Haverkamp, Wilhelm
,
van Soest, Eva M.
,
Mokhles, M. Mostafa
in
Biological and medical sciences
,
Clinical trial. Drug monitoring
,
Computer programs
2012
Background:
There is growing evidence that ergot dopamine agonists may induce cardiac valve regurgitation (CVR) in persons with Parkinson’s disease. It is unclear whether the CVR risk is increased with ergot-dopamine agonist use in persons with hyperprolactinaemia, in whom the dose is much lower.
Objective:
The aim of the study was to explore the association between different dopamine agonists and CVR in patients with Parkinson’s disease or hyperprolactinaemia.
Design:
Nested case-control studies conducted separately in cohorts of Parkinson’s disease and hyperprolactinaemia patients. Cases were patients who developed newly diagnosed CVR. Controls were CVR-free patients from the same cohorts and were matched to cases by age, sex, database and calendar year.
Setting and Patients:
Study patients were identified from over 4.5 million persons in The Health Improvement Network (THIN; UK), Health Search (Italy), and Integrated Primary Care Information (IPCI; the Netherlands) general practice databases in the years 1996–2007. The Parkinson’s disease cohort included new users of dopamine agonists or levodopa, while the hyperprolactinaemia cohort included new users or non-users of dopamine agonists.
Main Outcome Measure:
Risk of newly diagnosed CVR with dopamine agonist use compared with levodopa use in the Parkinson’s disease cohort, and dopamine agonist-naïve patients in the hyperprolactinaemia cohort.
Results:
In the Parkinson’s disease cohort (7893 dopamine agonist users, 11 766 levodopa users), 85 incident CVR cases were identified. Increased CVR risk was observed for ergot dopamine agonists (adjusted OR [OR
adj
] 3.82; 95% CI 2.14, 6.81), but not for non-ergot dopamine agonists (OR
adj
1.20; 95% CI 0.63, 2.29).
In the hyperprolactinaemia cohort (6740 dopamine agonist users and 14299 dopamine agonist-naïve patients), 37 CVR cases were identified during a mean follow-up of 4.5 years and 3.5 years for new users and non-users of dopamine agonists, respectively. However, no association with ever use of ergot dopamine agonists was observed (OR
adj
0.47; 95% CI 0.20,1.19).
Conclusion:
Ergot-derived dopamine agonists are associated with an increased risk of CVR in Parkinson’s disease but not in hyperprolactinaemia patients.
Journal Article
Marine Seagrass Extract of Thalassia testudinum Suppresses Colorectal Tumor Growth, Motility and Angiogenesis by Autophagic Stress and Immunogenic Cell Death Pathways
by
Herrera Isidrón, José Alfredo
,
dos Reis, Diego Carlos
,
Delgado-Roche, Livan
in
allografting
,
Angiogenesis
,
Animals
2021
Marine plants have become an inexhaustible reservoir of new phytopharmaceuticals for cancer treatment. We demonstrate in vitro/in vivo antitumor efficacy of a standardized polyphenol extract from the marine angiosperm Thalassia testudinum (TTE) in colon tumor cell lines (RKO, SW480, and CT26) and a syngeneic allograft murine colorectal cancer model. MTT assays revealed a dose-dependent decrease of cell viability of RKO, CT26, and SW480 cells upon TTE treatment with IC50 values of, respectively, 175, 115, and 60 μg/mL. Furthermore, TTE significantly prevented basal and bFGF-induced angiogenesis in the chicken chorioallantoic membrane angiogenesis assay. In addition, TTE suppressed bFGF-induced migration of endothelial cells in a wound closure assay. Finally, TTE treatment abrogated CT26 colorectal cancer growth and increased overall organism survival in a syngeneic murine allograft model. Corresponding transcriptome profiling and pathway analysis allowed for the identification of the mechanism of action for the antitumor effects of TTE. In line with our in vitro/in vivo results, TTE treatment triggers ATF4-P53-NFκB specific gene expression and autophagy stress pathways. This results in suppression of colon cancer cell growth, cell motility, and angiogenesis pathways in vitro and in addition promotes antitumor immunogenic cell death in vivo.
Journal Article
Nano-targeted induction of dual ferroptotic mechanisms eradicates high-risk neuroblastoma
by
Bayır, Hülya
,
Chirumamilla, Chandra Sekhar
,
Ekert, Paul G.
in
Analysis
,
Angiogenesis
,
Animals
2018
High-risk neuroblastoma is a devastating malignancy with very limited therapeutic options. Here, we identify withaferin A (WA) as a natural ferroptosis-inducing agent in neuroblastoma, which acts through a novel double-edged mechanism. WA dose-dependently either activates the nuclear factor-like 2 pathway through targeting of Kelch-like ECH-associated protein 1 (noncanonical ferroptosis induction) or inactivates glutathione peroxidase 4 (canonical ferroptosis induction). Noncanonical ferroptosis induction is characterized by an increase in intracellular labile Fe(II) upon excessive activation of heme oxygenase-1, which is sufficient to induce ferroptosis. This double-edged mechanism might explain the superior efficacy of WA as compared with etoposide or cisplatin in killing a heterogeneous panel of high-risk neuroblastoma cells, and in suppressing the growth and relapse rate of neuroblastoma xenografts. Nano-targeting of WA allows systemic application and suppressed tumor growth due to an enhanced accumulation at the tumor site. Collectively, our data propose a novel therapeutic strategy to efficiently kill cancer cells by ferroptosis.
Journal Article
Genome‐wide DNA methylation profiling and identification of potential pan‐cancer and tumor‐specific biomarkers
2022
DNA methylation alterations have already been linked to cancer, and their usefulness for therapy and diagnosis has encouraged research into the human epigenome. Several biomarker studies have focused on identifying cancer types individually, yet common cancer and multicancer markers are still underexplored. We used The Cancer Genome Atlas (TCGA) to investigate genome‐wide methylation profiles of 14 different cancer types and developed a three‐step computational approach to select candidate biomarker CpG sites. In total, 1991 pan‐cancer and between 75 and 1803 cancer‐specific differentially methylated CpG sites were discovered. Differentially methylated blocks and regions were also discovered for the first time on such a large scale. Through a three‐step computational approach, a combination of four pan‐cancer CpG markers was identified from these sites and externally validated (AUC = 0.90), maintaining comparable performance across tumor stages. Additionally, 20 tumor‐specific CpG markers were identified and made up the final type‐specific prediction model, which could accurately differentiate tumor types (AUC = 0.87–0.99). Our study highlights the power of the methylome as a rich source of cancer biomarkers, and the signatures we identified provide a new resource for understanding cancer mechanisms on the wider genomic scale with strong applicability in the context of new minimally invasive cancer detection assays. We used The Cancer Genome Atlas to study genome‐wide methylation profiles of 14 different cancer types. We identified and validated a combination of four candidate pan‐cancer methylation CpG biomarkers and 20 candidate cancer type‐specific markers. This highlights the methylome as a rich source of biomarkers which can be used in the context of new minimally invasive cancer detection assays.
Journal Article
Mutational spectrum of the WFS1 gene in Wolfram syndrome, nonsyndromic hearing impairment, diabetes mellitus, and psychiatric disease
by
Lesperance, Marci M.
,
Flothmann, Kris
,
Smith, Richard J.H.
in
Alternative Splicing
,
Base Sequence
,
Databases, Nucleic Acid
2003
WFS1 is a novel gene and encodes an 890 amino‐acid glycoprotein (wolframin), predominantly localized in the endoplasmic reticulum. Mutations in WFS1 underlie autosomal recessive Wolfram syndrome and autosomal dominant low frequency sensorineural hearing impairment (LFSNHI) DFNA6/14. In addition, several WFS1 sequence variants have been shown to be significantly associated with diabetes mellitus and this gene has also been implicated in psychiatric diseases. Wolfram syndrome is highly variable in its clinical manifestations, which include diabetes insipidus, diabetes mellitus, optic atrophy, and deafness. Wolfram syndrome mutations are spread over the entire coding region, and are typically inactivating, suggesting that a loss of function causes the disease phenotype. In contrast, only non‐inactivating mutations have been found in DFNA6/14 families, and these mutations are mainly located in the C‐terminal protein domain. In this paper, we provide an overview of the currently known disease‐causing and benign allele variants of WFS1 and propose a potential genotype–phenotype correlation for Wolfram syndrome and LFSNHI. Hum Mutat 22:275–287, 2003. © 2003 Wiley‐Liss, Inc.
Journal Article
Outcomes in patients with moderate and asymptomatic severe aortic stenosis followed up in heart valve clinics
2023
BackgroundHeart valve clinics (HVC) have been introduced to manage patients with valvular heart disease within a multidisciplinary team.ObjectiveTo determine the outcome benefit of HVC approach compared with standard of care (SOC) for patients with moderate and asymptomatic severe aortic stenosis (mAS and asAS).MethodsSingle-centre, observational registry of patients with mAS and asAS with at least one cardiac ambulatory consultation at our Cardiovascular Centre. Based on the outpatient strategy, patients were divided into HVC group, if receiving at least one visit at HVC, and SOC group, if followed by routine cardiac consultations.Results2129 patients with mAS and asAS were divided into those followed in HVC (n=251) versus SOC group (n=1878). The mean age was 76.5±12.4 years; 919 (43.2%) had asAS. During a follow-up of 4.8±1.8 years, 822 patients (38.6%) died, 307 (14.4%) were hospitalised for heart failure and 596 (28%) underwent aortic valve replacement (AVR). After propensity score matching, the number of consultations per year, exercise stress tests, brain natriuretic peptide (BNP) determinations and CTs were higher in the HVC cohort (p<0.05 for all). A shorter time between indication of AVR and less advanced New York Heart Association class was reported in the HVC cohort (p<0.001 and p=0.032). Compared with SOC, the HVC approach was associated with reduced all-cause mortality (HR=0.63, 95% CI 0.40 to 0.98, p=0.038) and cardiovascular death (p=0.030). At multivariable analysis, the HVC remained an independent predictor of all-cause mortality (HR=0.54, 95% CI 0.34 to 0.85, p=0.007).ConclusionsIn patients with mAS and asAS, the HVC approach was associated with more efficient management and outcome benefit compared with SOC.
Journal Article
Molecular diagnostics for congenital hearing loss including 15 deafness genes using a next generation sequencing platform
by
Scharlaken, Bieke
,
Van de Voorde, Hendrik
,
Deforce, Dieter
in
Biomedical and Life Sciences
,
Biomedicine
,
Connexin 26
2012
Background
Hereditary hearing loss (HL) can originate from mutations in one of many genes involved in the complex process of hearing. Identification of the genetic defects in patients is currently labor intensive and expensive. While screening with Sanger sequencing for
GJB2
mutations is common, this is not the case for the other known deafness genes (> 60). Next generation sequencing technology (NGS) has the potential to be much more cost efficient. Published methods mainly use hybridization based target enrichment procedures that are time saving and efficient, but lead to loss in sensitivity. In this study we used a semi-automated PCR amplification and NGS in order to combine high sensitivity, speed and cost efficiency.
Results
In this proof of concept study, we screened 15 autosomal recessive deafness genes in 5 patients with congenital genetic deafness. 646 specific primer pairs for all exons and most of the UTR of the 15 selected genes were designed using primerXL. Using patient specific identifiers, all amplicons were pooled and analyzed using the Roche 454 NGS technology. Three of these patients are members of families in which a region of interest has previously been characterized by linkage studies. In these, we were able to identify two new mutations in
CDH23
and
OTOF
. For another patient, the etiology of deafness was unclear, and no causal mutation was found. In a fifth patient, included as a positive control, we could confirm a known mutation in
TMC1.
Conclusions
We have developed an assay that holds great promise as a tool for screening patients with familial autosomal recessive nonsyndromal hearing loss (ARNSHL). For the first time, an efficient, reliable and cost effective genetic test, based on PCR enrichment, for newborns with undiagnosed deafness is available.
Journal Article