Publications by authors named "Mirian Janssen"

Background: This study aimed to explore the feasibility, safety and efficacy of a Modified Atkins Diet (MAD) in patients with mitochondrial myopathy (MM).

Methods: Patients with genetically proven mitochondrial disorder and exercise intolerance or muscle weakness followed a twelve week MAD. Feasibility was measured by diet duration and ketone levels.

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We here explore adverse events following immunization (AEFI) in children with mitochondrial disease (MD) recruited from two expertise centers in Austria (SALK) and The Netherlands (RUMC). Parents completed a questionnaire on the type of immunizations received and AEFI in a post-vaccination exposure period of seven days. 95 individuals were invited to this study, of whom 30 (median age 13.

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Article Synopsis
  • Mitochondrial disease is a rare condition currently lacking approved treatments, with sonlicromanol being a promising candidate that modifies key metabolic and inflammatory pathways.
  • A Phase 2b study was conducted to evaluate sonlicromanol's safety and efficacy in adults with a specific genetic mutation, involving both a randomized controlled trial (RCT) and a long-term extension study.
  • While the primary endpoint of the RCT didn't show significant results, there were indications of improvement in certain cognitive and emotional assessments among patients who were more affected at baseline.
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  • Paediatric Leigh syndrome (LS) is a severe neurodegenerative disorder caused by mutations in the NDUFS4 gene, which affects mitochondrial function, and currently has no effective treatments.
  • Researchers used whole-body Ndufs4 knockout (KO) mice to analyze differences in brain proteomes between these mice and wildtype mice, identifying variations across different brain regions.
  • Findings highlighted reduced levels of critical mitochondrial components in specific brain areas and suggested that attempts to stimulate certain metabolic pathways could be harmful, prompting the need for new therapeutic strategies for managing LS.
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Patients with classic galactosemia (CG), an inborn error of galactose metabolism, suffer from impairments in cognition, including language processing. Potential causes are atypical brain oscillations. Recent electroencephalogram (EEG) showed differences in the P300 event-related-potential (ERP) and alterations in the alpha/theta-range during speech planning.

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Objective: Classical galactosemia (CG) is an inborn error of galactose metabolism. Many CG patients suffer from long-term complications including poor cognitive functioning. There are indications of social dysfunction but limited evidence in the literature.

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Fragility fractures are frequently reported in neuromuscular diseases and negatively influence functional prognosis, quality of life and survival. In LAMA2-related muscular dystrophy (LAMA2-MD) and SELENON(SEPN1)-related congenital myopathy (SELENON-RM) cross-sectional and prospective natural history studies on bone quality and fragility long bone fractures (LBFs) are lacking. We therefore aim to systematically assess bone quality and provide recommendations for clinical care.

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Article Synopsis
  • - SELENON-related myopathy (SELENON-RM) is a rare genetic condition causing issues like muscle weakness, spinal stiffness, and respiratory problems, with no treatment options available yet, prompting ongoing research.
  • - An observational study in the Netherlands assessed 11 genetically confirmed SELENON-RM patients focusing on clinical symptoms, functional capabilities, and quality of life through various tests and questionnaires.
  • - Findings highlighted severe muscle weakness, impaired respiratory function, and complications like decreased bone density and cardiac strain, indicating significant health challenges for these patients.
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Background: Newborn screening (NBS) programmes identify a wide range of disease phenotypes, which raises the question whether early identification and treatment is beneficial for all. This study aims to answer this question for primary carnitine deficiency (PCD) taking into account that NBS for PCD identifies newborns with PCD and also until then undiagnosed mothers.

Methods: We investigated clinical, genetic (variants in gene) and functional (carnitine transport activity in fibroblasts) characteristics of all referred individuals through NBS (newborns and mothers) and clinically diagnosed patients with PCD (not through NBS).

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Background: Eating an adequate diet and maintaining a healthy body weight can be challenging for patients with muscular disorders (MD). Starting tube feeding can have a positive impact on nutritional status, functioning and quality of life. Guidelines on when to start tube feeding in adults with MD are lacking.

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Background And Objectives: -related muscular dystrophy (-MD) is a rare neuromuscular disease characterized by proximal and axial muscle weakness, rigidity of the spine, scoliosis, and respiratory impairment. No curative treatment options exist, yet promising preclinical studies are ongoing. Currently, there is a paucity on natural history data, and appropriate clinical and functional outcome measures are needed.

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Amongst a cohort of 88 alkaptonuria (AKU) patients attending the United Kingdom National Alkaptonuria Centre (NAC), four unrelated patients had co-existing Parkinson's disease (PD). Two of the NAC patients developed PD before receiving nitisinone (NIT) while the other two developed overt PD during NIT therapy. NIT lowers redox-active homogentisic acid (HGA) and profoundly increases tyrosine (TYR).

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Mitochondrial diseases are the most common inborn errors of metabolism. These severe multisystem disorders cause serious morbidity and mortality. Generally no treatment is available.

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Background: Congenital myopathies are rare neuromuscular disorders presenting with a wide spectrum of clinical features, including long bone fractures (LBFs) that negatively influence functional prognosis, quality of life and survival. Systematic research on bone quality in these patients is lacking.

Objective: This scoping review aims to summarize all evidence on bone quality and to deduce recommendations for bone quality management in congenital myopathies.

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Background: Studies regarding cognitive and mental health functioning in children with mitochondrial disease (MD) are scarce, while both are important issues given their impact on QoL. Knowledge on these aspects of functioning and its relationship with disease parameters is essential to gather more insight in working mechanisms and provide recommendations for future research and patientcare. The aim of this study was to map the cognitive functioning and mental health in children with MD in relation to disease specific factors.

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Infantile nephropathic cystinosis (INC) is an inheritable lysosomal storage disorder characterized by lysosomal cystine accumulation, progressive kidney disease, and multiple extrarenal complications (ERCs). Cysteamine postpones the onset of end-stage kidney disease (ESKD) and reduces the incidence of ERCs; however, cysteamine is generally initiated upon establishment of the renal Fanconi syndrome (FS) and partial loss of kidney function, whereas data on long-term effects of cysteamine administered from neonatal age are lacking. An international multicenter retrospective cohort study of siblings with INC was set up to investigate the outcome in relation to age at initiation of cysteamine versus CTNS genotype, with attention to patients treated with cysteamine from neonatal age.

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Severe fatigue is a common complaint in patients with primary mitochondrial disease. However, less is known about the course of fatigue over time. This longitudinal observational cohort study of patients with the mitochondrial DNA 3243 A>G variant explored trajectories of fatigue over 2 years, and characteristics of patients within these fatigue trajectories.

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Classical galactosemia (CG) is one of the more frequent inborn errors of metabolism affecting approximately 1:40.000 people. Despite a life-saving galactose-restricted diet, patients develop highly variable long-term complications including intellectual disability and movement disorders.

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Background And Objectives: Pyridoxine-dependent epilepsy (PDE-ALDH7A1) is a developmental epileptic encephalopathy characterized by seizure improvement after pyridoxine supplementation. Adjunct lysine reduction therapies (LRTs) reduce the accumulation of putative neurotoxic metabolites with the goal to improve developmental outcomes. Our objective was to examine the association between treatment with LRTs and cognitive outcomes.

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Background: Previous studies in patients with a mitochondrial disease (MD) highlight the high prevalence of cognitive impairments, fatigue, depression, and a lower quality of life (QoL). The relationship with biological and physiological factors remains complex. The aim of this study is to investigate the status of and interrelationships between biological and physiological functioning, cognitive functioning as well as fatigue, depression, societal participation, health perceptions, and QoL, by using the Wilson and Cleary conceptual disease model, adapted to MD.

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Background & Aims: Glycogen storage disease type Ia (GSDIa) is an inborn error of carbohydrate metabolism caused by pathogenic variants in the glucose-6-phosphatase catalytic subunit 1 () gene and is associated with hepatocellular adenoma (HCA) formation. Data on risk factors for HCA occurrence in GSDIa are scarce. We investigated HCA development in relation to sex, genotype, and serum triglyceride concentration (TG).

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Tyrosinemia type 1 (TT1) and phenylketonuria (PKU) are both inborn errors of phenylalanine-tyrosine metabolism. Neurocognitive and behavioral outcomes have always featured in PKU research but received less attention in TT1 research. This study aimed to investigate and compare neurocognitive, behavioral, and social outcomes of treated TT1 and PKU patients.

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Cystinosis is a rare autosomal recessive disease leading to end-stage renal disease within the second or third decade of life. Since the era of specific treatment with cysteamine, prognosis has substantially improved and pregnancy becomes an increasing concern. Pregnancy data in patients with cystinosis were collected through an anonymized survey.

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