Publications by authors named "Annet Simons"

Background: Limited data exist on persons with rare bleeding disorders possessing a heterozygous genotype, as most studies focus on biallelic genotypes and more severe coagulation factor deficiencies. A growing body of evidence suggests that persons with a heterozygous genotype experience clinically relevant bleeding symptoms.

Objectives: This study aimed to explore the incidence of bleeding symptoms and postoperative bleeding in persons with a heterozygous genotype.

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While next generation sequencing has expanded the scientific understanding of Inborn Errors of Immunity (IEI), the clinical use and re-use of exome sequencing is still emerging. We revisited clinical exome data from 1300 IEI patients using an updated in silico IEI gene panel. Variants were classified and curated through expert review.

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Background: Rare coagulation factor deficiencies and disorders of fibrinolysis (defined as rare bleeding disorders [RBDs]) present with a heterogeneous bleeding phenotype, and bleeding severity is difficult to predict.

Objectives: Describe underlying rare genetic variants in the Dutch RBD population and investigate the relationship between genotype, laboratory phenotype, and clinical phenotype.

Methods: The Rare Bleeding Disorders in the Netherlands is a cross-sectional, nationwide study conducted between October 1, 2017, and November 30, 2019.

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  • The genomics era has led to the identification of the ERG gene as a new autosomal dominant predisposition factor for bone marrow failure (BMF) and hematological malignancies (HM), crucial for blood cell development and function.
  • Research found several rare ERG variants associated with thrombocytopenia and various forms of HM, showing onset typically before age 40.
  • Functional studies indicated that many ERG variants disrupt its role as a transcription factor, leading to ineffective blood cell production, with implications for clinical diagnosis and treatment strategies for affected patients and families.
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Mutations in proteasome β-subunits or their chaperone and regulatory proteins are associated with proteasome-associated autoinflammatory disorders (PRAAS). We studied six unrelated infants with three de novo heterozygous missense variants in PSMB10, encoding the proteasome β2i-subunit. Individuals presented with T-B-NK± severe combined immunodeficiency (SCID) and clinical features suggestive of Omenn syndrome, including diarrhea, alopecia, and desquamating erythematous rash.

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  • Rapid exome sequencing (rES) is becoming the go-to genetic test for critically ill patients, especially neonates and young infants, helping quickly identify genetic causes of rare diseases to guide treatment.
  • A study evaluated rES on 575 patients over four years, revealing a significant increase in referrals and a decrease in turnaround time for results, with an overall diagnostic yield of 30.4%.
  • Even when no genetic diagnosis was found, rES still influenced clinical decision-making, highlighting its value for patients of all ages and various rare conditions.
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Here, we describe an adult female with severe fasciitis and skin necrosis who carried a private, predicted deleterious missense mutation in OTULIN in heterozygosity. OTULIN is a cellular regulator of deubiquitination that has been shown to play a key role in intrinsic immunity against staphylococcal α-toxin. The patient was treated with broad-spectrum antibiotics, and multiple surgical explorations were conducted without clinical response.

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Introduction: Chronic inflammatory or autoimmune diseases are commonly treated with immunosuppressive medication such as NSAIDs, corticosteroids, or antibodies against specific cytokines (TNF, IL-1 IL-17, IL-23, etc.) or signalling cascades (e.g.

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  • A study investigates the impact of evaluating rare de novo variants (DNVs) in whole exome sequencing (WES) for patients suspected of having inborn errors of immunity (IEI).
  • In a cohort of 123 patients, systematic assessment of DNVs led to identifying 14 potential candidates linked to immune functions, resulting in molecular diagnoses for some patients.
  • The research advocates for incorporating trio-based sequencing in routine diagnostics, providing evidence that certain loss-of-function mutations contribute to autoinflammatory diseases.
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  • Inborn errors of immunity (IEI) are diverse disorders affecting the immune system, with over 450 related genes identified, making next-generation sequencing (NGS) a promising diagnostic tool.
  • A study involving 165 patients suspected of having IEI found that NGS resulted in a definitive diagnosis for 24.6% of pediatric patients and 9% of adults, with most diagnoses falling under immune dysregulation and antibody deficiencies.
  • The median time from consultation to diagnosis was similar for both groups, and 76% of patients with a genetic diagnosis experienced changes in their disease management based on the results.
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Background: An appropriate clinical diagnosis of von Willebrand disease (VWD) can be challenging because of a variable bleeding pattern and laboratory phenotype. Genotyping is a powerful diagnostic tool and may have an essential role in the diagnostic field of VWD.

Objectives: To unravel the clinical and laboratory heterogeneity of genetically confirmed VWD type 2M patients and to investigate their relationship.

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  • Recent research found loss-of-function variants in a small number of males that may increase susceptibility to severe COVID-19, focusing on young men aged 18-50 without major health issues.
  • In a study of 14 patients, two had missense variants linked to severe COVID-19, with both variants being novel and potentially harmful.
  • The findings highlight the importance of genetic screening for these variants in young men with severe COVID-19, as it could guide treatment and help identify at-risk family members for early intervention.
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  • A new disease called VEXAS affects older men who have specific mutations in a gene called UBA1, leading to serious inflammation and health problems.
  • The study looked back at records of patients who had been diagnosed with unclear autoinflammatory issues to find cases of VEXAS.
  • Twelve men were found with this disease, which often doesn’t respond to treatment and can lead to serious complications, emphasizing the importance of early diagnosis for better care.
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Objectives: Complete deficiency of alternative pathway (AP) complement factors, explained by homozygous mutations, is a well-known risk factor for invasive bacterial infections; however, this is less obvious for heterozygous mutations. We describe two siblings with a heterozygous NM_001928.3(CFD):c.

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Dutch genome diagnostic centers (GDC) use next-generation sequencing (NGS)-based diagnostic applications for the diagnosis of primary immunodeficiencies (PIDs). The interpretation of genetic variants in many PIDs is complicated because of the phenotypic and genetic heterogeneity. To analyze uniformity of variant filtering, interpretation, and reporting in NGS-based diagnostics for PID, an external quality assessment was performed.

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Importance: Severe coronavirus disease 2019 (COVID-19) can occur in younger, predominantly male, patients without preexisting medical conditions. Some individuals may have primary immunodeficiencies that predispose to severe infections caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Objective: To explore the presence of genetic variants associated with primary immunodeficiencies among young patients with COVID-19.

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Breast cancer treatment depends on human epidermal growth factor receptor-2 (HER2) status, which is often determined using dual probe fluorescence in situ hybridisation (FISH). Hereby, also loss and gain of the centromere of chromosome 17 (CEP17) can be observed (HER2 is located on chromosome 17). CEP17 gain can lead to difficulty in interpretation of HER2 status, since this might represent true polysomy.

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Background: Diagnosis of primary immunodeficiencies (PIDs) is complex and cumbersome yet important for the clinical management of the disease. Exome sequencing may provide a genetic diagnosis in a significant number of patients in a single genetic test.

Methods: In May 2013, we implemented exome sequencing in routine diagnostics for patients suffering from PIDs.

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Introduction: Bleeding assessment tools and laboratory phenotyping often remain inconclusive in patients with a haemorrhagic diathesis.

Aim: To describe the phenotype and genetic profile of patients with a bleeding tendency.

Methods: Whole exome sequencing (WES) was incorporated in the routine diagnostic pathway of patients with thrombocytopenia (n = 17), platelet function disorders (n = 19) and an unexplained bleeding tendency (n = 51).

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variants have previously been described in patients with myopathy, lactic acidosis and sideroblastic anemia 2 (MLASA2). encodes the mitochondrial tyrosyl-tRNA synthetase, which is responsible for conjugating tyrosine to its cognate mt-tRNA for mitochondrial protein synthesis. Here we describe 14 individuals from 11 families presenting with sideroblastic anemia and variants that we identified using a sideroblastic anemia gene panel or exome sequencing.

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Purpose: Copy-number variation is a common source of genomic variation and an important genetic cause of disease. Microarray-based analysis of copy-number variants (CNVs) has become a first-tier diagnostic test for patients with neurodevelopmental disorders, with a diagnostic yield of 10-20%. However, for most other genetic disorders, the role of CNVs is less clear and most diagnostic genetic studies are generally limited to the study of single-nucleotide variants (SNVs) and other small variants.

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A standardized nomenclature is critical for the accurate and consistent description of genomic changes as identified by karyotyping, fluorescence in situ hybridization and microarray. The International System for Human Cytogenomic Nomenclature (ISCN) is the central reference for the description of karyotyping, FISH, and microarray results, and provides rules for describing cytogenetic and molecular cytogenetic findings in laboratory reports. These laboratory reports are documents to the referring clinician, and should be clear, accurate and contain all information relevant for good interpretation of the cytogenetic findings.

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