Publications by authors named "Zenker M"

The aim of this study was to determine the frequency-temperature dependence of the AC conductivity and relaxation times in humid electrical pressboard used in the insulation of power transformers, impregnated with the innovative NYTRO BIO 300X bio-oil produced from plant raw materials. Tests were carried out for a composite of cellulose-bio-oil-water nanodroplets with a moisture content of 0.6% by weight to 5% by weight in the frequency range from 10 Hz to 5·10 Hz.

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Rasopathies are genetic disorders often associated with developmental delay and intellectual disability. Noonan syndrome (NS) is one of the most common Rasopathies, caused by mutations in PTPN11 in more than 50% of cases. In mammalian neurons, PTPN11 controls the trafficking of postsynaptic glutamate receptors.

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Article Synopsis
  • The study aims to assess the cancer risks associated with multi-lineage mosaic RASopathies that have pathogenic variants in HRAS or KRAS.
  • A systematic review was conducted, identifying 69 patients, revealing a 17% cancer prevalence among them, with various types, notably rhabdomyosarcoma.
  • Findings indicate a 20% cumulative cancer incidence by age 20 and emphasize the importance of close monitoring for rhabdomyosarcoma in young children and skin cancer in adults with these conditions.
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Purpose: Pathogenic LZTR1 variants cause schwannomatosis and dominant/recessive Noonan syndrome (NS). We aim to establish an association between heterozygous loss-of-function LZTR1 alleles and isolated multiple café-au-lait macules (CaLMs).

Methods: A total of 849 unrelated participants with multiple CaLMs, lacking pathogenic/likely pathogenic NF1 and SPRED1 variants, underwent RASopathy gene panel sequencing.

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Myhre syndrome (MS, MIM 139210) is a rare multisystemic disorder caused by recurrent pathogenic missense variants in SMAD4. The clinical features have been mainly documented in childhood and comprise variable neurocognitive development, recognizable craniofacial features, a short stature with a pseudo-muscular build, hearing loss, thickened skin, joint limitations, diverse cardiovascular and airway manifestations, and increased fibrosis often following trauma or surgery. In contrast, adults with MS are underreported obscuring potential clinical variability.

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Arteriovenous malformations (AVM) are benign vascular anomalies prone to pain, bleeding, and progressive growth. AVM are mainly caused by mosaic pathogenic variants of the RAS-MAPK pathway. However, a causative variant is not identified in all patients.

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Anastomotic leakage (AL) is a potentially life-threatening complication following colorectal cancer (CRC) resection. In this study, we aimed to unravel longitudinal changes in microbial structure before, during, and after surgery and to determine if microbial alterations may be predictive for risk assessment between sufficient anastomotic healing (AS) and AL prior surgery. We analysed the microbiota of 134 colon mucosal biopsies with 16S rRNA V1-V2 gene sequencing.

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Noonan syndrome (NS) is an autosomal dominant condition characterized by facial dysmorphism, congenital heart disease, development delay, growth retardation and lymphatic disease. It is caused by germline pathogenic variants in genes encoding proteins in the Ras/mitogen-activated protein kinase signaling pathway. Nerve enlargement is not generally considered as a feature of NS, although some cases have been reported.

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RASopathies are a group of genetic disorders caused by mutations in genes encoding components and regulators of the RAS/MAPK signaling pathway, resulting in overactivation of signaling. RASopathy patients exhibit distinctive facial features, cardiopathies, growth and skeletal abnormalities, and varying degrees of neurocognitive impairments including neurodevelopmental delay, intellectual disabilities, or attention deficits. At present, it is unclear how RASopathy mutations cause neurocognitive impairment and what their neuron-specific cellular and network phenotypes are.

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According to a growing body of neurobiological evidence, the core symptoms of borderline personality disorder (BPD) may be linked to an opioidergic imbalance between the hedonic and stimulatory activity of mu opioid receptors (MOR) and the reward system inhibiting effects of kappa opioid receptors (KOR). Childhood trauma (CT), which is etiologically relevant to BPD, is also likely to lead to epigenetic and neurobiological adaptations by extensive activation of the stress and endogenous opioid systems. In this study, we investigated the methylation differences in the promoter of the KOR gene (OPRK1) in subjects with BPD (N = 47) and healthy controls (N = 48).

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Pathogenic, largely truncating variants in the ETS2 repressor factor (ERF) gene, encoding a transcriptional regulator negatively controlling RAS-MAPK signaling, have been associated with syndromic craniosynostosis involving various cranial sutures and Chitayat syndrome, an ultrarare condition with respiratory distress, skeletal anomalies, and facial dysmorphism. Recently, a single patient with craniosynostosis and a phenotype resembling Noonan syndrome (NS), the most common disorder among the RASopathies, was reported to carry a de novo loss-of-function variant in ERF. Here, we clinically profile 26 individuals from 15 unrelated families carrying different germline heterozygous variants in ERF and showing a phenotype reminiscent of NS.

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Background: Vascular anomalies caused by somatic (postzygotic) variants are clinically and genetically heterogeneous diseases with overlapping or distinct entities. The genetic knowledge in this field is rapidly growing, and genetic testing is now part of the diagnostic workup alongside the clinical, radiological and histopathological data. Nonetheless, access to genetic testing is still limited, and there is significant heterogeneity across the approaches used by the diagnostic laboratories, with direct consequences on test sensitivity and accuracy.

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Despite linkage to chromosome 16q in 1996, the mutation causing spinocerebellar ataxia type 4 (SCA4), a late-onset sensory and cerebellar ataxia, remained unknown. Here, using long-read single-strand whole-genome sequencing (LR-GS), we identified a heterozygous GGC-repeat expansion in a large Utah pedigree encoding polyglycine (polyG) in zinc finger homeobox protein 3 (ZFHX3), also known as AT-binding transcription factor 1 (ATBF1). We queried 6,495 genome sequencing datasets and identified the repeat expansion in seven additional pedigrees.

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Background: We aimed to correlate alterations in the rat sarcoma virus (RAS)/mitogen-activated protein kinase pathway in vascular anomalies to the clinical phenotype for improved patient and treatment stratification.

Methods And Results: This retrospective multicenter cohort study included 29 patients with extracranial vascular anomalies containing mosaic pathogenic variants (PVs) in genes of the RAS/mitogen-activated protein kinase pathway. Tissue samples were collected during invasive treatment or clinically indicated biopsies.

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Recent pan-cancer genomic analyses have identified numerous oncogenic driver mutations that occur in a cell-type and tissue-specific distribution. For example, oncogenic mutations in Braf and Nras genes arise predominantly in melanocytic neoplasms of the epidermis, while oncogenic mutations in Gnaq/11 genes arise mostly in melanocytic lesions of the dermis or the uvea. The mechanisms promoting cell-type and tissue-specific oncogenic events currently remain poorly understood.

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Intellectual disability has a prevalence rate of approximately 1% of the population; in Germany, this is around 0.5-1 million people. The life expectancy of this group of people is reduced, with cancer being one of the most common causes of death (approx.

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Article Synopsis
  • * The 8th International RASopathies Symposium highlighted global cooperation in clinical care and research, focusing on building diverse patient groups and sharing discoveries to prepare for future interventional trials.
  • * The event included presentations from various stakeholders, including scientists and self-advocates, aimed at bridging knowledge gaps and fostering long-term research and advocacy partnerships to improve health outcomes for those with RASopathies.
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  • Juvenile myelomonocytic leukaemia (JMML) is a type of cancer that occurs in children and is linked to problems with certain genes in the RAS pathway.
  • Kids with a condition called neurofibromatosis type 1 (NF-1) are more likely to get JMML because of a faulty NF1 gene they inherit.
  • The study looked at 25 JMML patients, finding different types of NF1 gene problems and suggesting that testing for NF1 gene issues is important even if patients don’t show signs of NF-1.
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Treatment-resistant epilepsy is among the most serious complications of cardiofaciocutaneous syndrome (CFCS), a rare disorder caused by germline variants in the RAS-MAPK signaling pathway. This study analyzed the clinical characteristics of epilepsy and response to anti-seizure medications (ASMs) in a multinational CFCS cohort. A caregiver survey provided data regarding seizure history, use of ASMs and other treatment approaches, adverse effects, caregiver perception of treatment response, and neurological disease burden impact among individuals with CFCS.

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  • - RASopathies contribute to about 20% of childhood hypertrophic cardiomyopathy (HCM) cases and are linked to a risk of sudden cardiac death (SCD), but the specific risk factors for SCD in this group hadn’t been thoroughly researched until now.
  • - The study analyzed 169 children with RASopathy-related HCM across 15 cardiology centers and found that 6.5% experienced SCD or similar events, with many of those categorized as low risk by the existing HCM Risk-Kids model.
  • - Key predictors for SCD identified were unexplained syncope and non-sustained ventricular tachycardia, indicating that the current risk prediction model may not effectively identify risks in this
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  • Early life microbial infections pose challenges to the developing immune system, and the study examines how T-helper cell responses vary between age groups and pathogens, particularly in the context of the SARS-CoV-2 pandemic.* -
  • The research highlights that T-cells responding to Staphylococcus species differentiate into Th1-type cells, while T-cells activated by Bifidobacterium longum infantis show a suppressive effect on Staphylococcus-specific T-helper cells through mechanisms like increased IL-10 production.* -
  • Bifidobacterium's ability to modulate immune responses may play a role in reducing harmful effects in severely ill COVID-19 patients, suggesting that tailored interventions based on age and immune characteristics could improve infection
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C-terminal variants in CDC42 encoding cell division control protein 42 homolog underlie neonatal-onset cytopenia, autoinflammation, rash, and hemophagocytic lymphohistiocytosis (NOCARH). Pyrin inflammasome hyperactivation has been shown to contribute to disease pathophysiology. However, mortality of NOCARH patients remains high despite inflammasome-focused treatments.

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