232 research outputs found
A Novel PEX13 Variant Causes Zellweger Spectrum Disorder with Mild/Intermediate Phenotype and Cystic Leukoencephalopathy
No full textMaternal segmental disomy in Leigh syndrome with cytochrome c oxidase deficiency caused by homozygous SURF1 mutation
No full textCytochrome c okidase deficiency (COX) is the most frequent cause of Leigh syndrome (LS), a mitochondrial subacute necrotizing encephalomyelopathy. Most of these LSCOX- patients show mutations in SURF1 on chromosome 9 (9q34), which encodes a protein essential for the assembly of the COX complex. We describe a family whose first-born boy developed characteristic features of LS. Severe COX deficiency in muscle was caused by a novel homozygous nonsense mutation in SURF1. Segregation analysis of this mutation in the family was incompatible with autosomal recessive inheritence but consistent with a maternal disomy. Haplotype analysis of microsatellite markers confirmed isodisomy involving nearly the complete long arm of chromosome 9 (9q21-9tel). No additional physical abnormalities were present in the boy, suggesting that there are no imprinted genes on the long arm of chromosome 9 which are crucial for developmental processes. This case of segmental isodisomy illustrates that genotyping of parents is crucial for correct genetic counseling
Familial mitochondrial myopathy and diabetes mellitus due to a rare mtDNA mutation (tRNAGlu 14.709T > C): clinical presentation and therapeutical effects
No full textFamilial mitochondrial myopathy and diabetes mellitus due to a rare mtDNA mutation (tRNAGlu 14.709T > C): clinical presentation and therapeutical effects
No full textNetwork mechanisms in rapid-onset dystonia-parkinsonism
No full textRapid-onset dystonia-parkinsonism (RDP) is a rare neurological disorder caused by mutations in the ATP1A3 gene. Symptoms are characterized by a dystonia-parkinsonism. Recently, experimental studies have shown that the pathophysiology of the disease is based on a combined dysfunction of the cerebellum (CB) and basal ganglia (BG) and that blocking their interaction can alleviate the symptoms. The underlying network mechanisms have not been studied so far. Our aim was to characterize neuronal network activity in the BG and CB and motor cortex in the ouabain model of RDP by site-specific infusion of ouabain. Rats were chronically infused with ouabain either in the CB, striatum (STR) or at both places simultaneously. Motor behavior was scored using published rating systems. Parallel in vivo recordings of local field potentials (LFP) from M1, deep cerebellar nuclei (DCN) and substantia nigra reticulata (SNr) were performed. Data were compared to untreated controls. Ouabain infusion into the cerebellum produced severe dystonia that was associated with increased high-frequency gamma oscillations in the DCNs, which were subsequently transmitted to the BG and M1. Striatal infusion led to parkinsonism and elevated beta-oscillations in SNr that were transmitted to the CB and M1. The simultaneous application of STRs and CB with ouabain resulted in dystonia-parkinsonism and increased beta oscillations in BG, CB, and M1.We demonstrate that symptom-specific beta and gamma oscillations can be transmitted between the BG and CB, which is likely to be very important for the understanding of disease mechanisms
Recognizable pattern of arthrogryposis and congenital myopathy caused by the recurrent TTN metatranscript-only c.39974-11T>G splice variant
No full textIntroduction:Arthrogryposis is characterized by the presence of multiple contractures at birth and can be caused by pathogenic variants in TTN (Titin). Exons and variants that are not expressed in one of the three major isoforms of titin are referred to as “metatranscript-only” and have been considered to be only expressed during fetal development. Recently, the metatranscript-only variant (c.39974-11T>G) in TTN with a second truncating TTN variant has been linked to arthrogryposis multiplex congenita and myopathy. Methods: Via exome sequencing we identified the TTN c.39974-11T>G splice variant in trans with one of three truncating variants (p.Arg8922 , p.Lys32998Asnfs 63), p.Tyr10345 ) in five individuals from three families. Clinical presentation and muscle ultrasound as well as MRI images were analyzed. Results: All five patients presented with generalized muscular hypotonia, reduced muscle bulk and congenital contractures most prominently affecting the upper limbs and distal joints. Muscular hypotonia persisted and contractures improved over time. One individual, the recipient twin in the setting of twin-to-twin transfusion syndrome, died from severe cardiac hypertrophy one day after birth. Ultrasound and MRI imaging studies revealed a recognizable pattern of muscle involvement with striking fibrofatty involvement in the hamstrings and calves, and relative sparing of the femoral adductors and anterior segment of the thighs. Conclusion:The recurrent TTN c.39974-11T>G variant consistently causes congenital arthrogryposis and persisting myopathy providing evidence that the metatranscript-only 213-217 exons impact muscle elasticity during early development and beyond. There is a recognizable pattern of muscle involvement, which is distinct from other myopathies and provides valuable clues for diagnostic work
The relevance of synuclein autoantibodies as a biomarker for Parkinson's disease
No full textSeveral studies have investigated if the levels of α-synuclein autoantibodies (α-syn AAb) differ in serum of Parkinson's disease (PD) patients and healthy subjects. Reproducible differences in their levels could serve as a biomarker for PD. The results of previous studies however remain inconclusive. With the largest sample size examined so far, we aimed to validate serum α-syn AAb levels as a biomarker for PD and investigated the presence of AAbs against other synucleins. We performed ELISA and immunoblots to determine synuclein AAb levels in the serum of 295 subjects comprising 157 PD patients from two independent cohorts, 46 healthy subjects, and 92 patients with other neurodegenerative disorders. Although serum α- and β-syn AAb levels were significantly reduced in patients with PD and other neurodegenerative disorders as compared to controls, the AAb levels displayed high inter-and intra-cohort variability. Furthermore, α-syn AAb levels showed no correlation to clinical parameters like age, disease duration, disease severity, and gender, that might also be directed against beta- and gamma-syn. In conclusion, serum synuclein AAb levels do allow the separation of PD from healthy subjects but not from other neurodegenerative disorders. Thus, synuclein AAbs cannot be regarded as a reliable biomarker for PD
Ectosomes and exosomes modulate neuronal spontaneous activity
No full textExtracellular vesicles (EVs) are important mediators in intercellular communication. However, understanding the biological origin and functional effects of EVs subtypes has been challenging due to the moderate differences in their physical properties and absence of reliable markers. Here, we characterize the proteomes of ectosomes and exosomes using an improved differential ultracentrifugation protocol and quantitative proteomics. Our analyses revealed singular proteomic profiles for ectosomes and exosomes that enabled us to establish specific protein markers that can be used for their biochemical distinction. Cytoskeleton and glycolytic proteins are distinctively present in ectosomes, while endosomal sorting complexes proteins and tetraspanins are enriched in exosomes. Furthermore, annexin-A2 was identified as a specific marker for ectosomes derived from cell media and human cerebrospinal fluid. Expression of EGFP as a cytosolic reporter leads to its incorporation in EVs and enables their imaging with higher resolution. Assessment of neuronal network activity using multi-electrode array recordings demonstrated that spontaneous neuronal activity can be modulated by EVs. Ectosomes and exosomes internalization in neuronal cells disrupted their regular synchronized bursting activity, resulting in overall lower and more disorganized spiking activity. Our findings suggest that EVs cargoes reflect core intracellular processes, and their functional properties might regulate basic biological and pathological processes
Myelin basic protein and TREM2 quantification in the CSF of patients with Multiple System Atrophy and other Parkinsonian conditions
No full textAbstract Background It is well known that myelin disruption and neuroinflammation are early and distinct pathological hallmarks in multiple system atrophy (MSA) as well as in idiopathic Parkinson’s disease and in other atypical Parkinsonian syndromes. The objective of this study was to assess the value of non-neuronal biomarker candidates that reflect myelin disruption and neuroinflammation. Methods Myelin basic protein (MBP) and the soluble form of TREM2 were quantified in a comprehensive movement disorder cohort from two different neurological centers, comprising a total of 171 CSF samples. Commercially available ELISA systems were employed for quantification. Results The results of the MBP analysis revealed a significant increase in cerebrospinal fluid (CSF) MBP levels in all atypical Parkinsonian conditions compared to PD. This differentiation was more pronounced in the MSA-c subtype compared to MSA-p. Receiver operating characteristic (ROC) analysis revealed a significant discrimination between PD and MSA ( p = 0.032, AUC = 0.70), PD and DLB ( p = 0.006, AUC = 0.79) and PD and tauopathies ( p = 0.006, AUC = 0.74). The results of the TREM2 analysis demonstrated no significant differences between the PD and atypical Parkinsonian groups if not adjusted for confounders. After adjusting for age, sex, and disease duration, the PD group exhibited significantly higher TREM2 levels compared to the DLB group ( p = 0.002). Conclusions In conclusion, MBP, but not TREM2, is elevated in the CSF of not only MSA but in all atypical Parkinsonian conditions compared to idiopathic Parkinson’s disease. This highlights the value of the evaluation of myelin/oligodendrocyte-associated markers in neurodegenerative movement disorders
Subthalamic beta oscillations correlate with dopaminergic degeneration in experimental Parkinsonism
No full textExcessive beta activity has been shown in local field potential recordings from the cortico-basal ganglia loop of Parkinson's disease patients and in its various animal models. Recent evidence suggests that enhanced beta oscillations may play a central role in the pathophysiology of the disorder and that beta activity may be directly linked to the motor impairment. However, the temporal evolution of exaggerated beta oscillations during the ongoing dopaminergic neurodegeneration and its relation to the motor impairment and histological changes are still unknown. We investigated motor behavioral, in-vivo electrophysiological (subthalamic nucleus, motor cortex) and histological changes (striatum, substantia nigra compacta) 2, 5, 10 and 20–30 days after a 6-hydroxydopamine injection into the medial forebrain bundle in Wistar rats.We found strong correlations between subthalamic beta power and motor impairment. No correlation was found for beta power in the primary motor cortex. Only subthalamic but not cortical beta power was strongly correlated with the histological markers of the dopaminergic neurodegeneration. Significantly increased subthalamic beta oscillations could be detected before this increase was found in primary motor cortex. At the latest observation time point, a significantly higher percentage of long beta bursts was found. Our study is the first to show a strong relation between subthalamic beta power and the dopaminergic neurodegeneration. Thus, we provide additional evidence for an important pathophysiological role of subthalamic beta oscillations and prolonged beta bursts in Parkinson's disease
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