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Inherited Neuropathy (inherited + neuropathy)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

The effect of myelinating Schwann cells on axons

MUSCLE AND NERVE, Issue 4 2001
Rudolf Martini PhD
Abstract Myelinating Schwann cells control the number of neurofilaments and elevate the phosphorylation state of neurofilaments in the axon, eventually leading to the typical large axon caliber. Conversely, absence of myelin leads to lower amounts of neurofilaments, reduced phosphorylation levels, and smaller axon diameters. In addition, myelinating Schwann cells mediate the spacing of Na+ channel clusters during development of the node of Ranvier. When axons are associated with mutant Schwann cells in inherited neuropathies, their calibers are reduced and their neurofilaments are less phosphorylated and more closely spaced. Also, axonal transport is reduced and axons degenerate at the distal ends of long nerves. Myelin-associated glycoprotein may mediate some aspects of Schwann cell,axon communication, but much remains to be learned about the molecular bases of Schwann cell,axon communication. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 456,466, 2001 [source]

Penetrance estimation of TTR familial amyloid polyneuropathy (type I) in Brazilian families

EUROPEAN JOURNAL OF NEUROLOGY, Issue 3 2009
M. A. C. Saporta
Background and purpose:, Familial amyloid polyneuropathy (FAP) type I is a severe autosomal dominant inherited neuropathy associated with mutations in the transthyretin (TTR) gene. Significant phenotypic variability is seen amongst families with distinct geographic origin, especially regarding penetrance and age of onset. The aim of this study was to estimate the penetrance of FAP in Brazilian families. Methods:, Twenty-two distinct families were ascertained through genetically confirmed index cases and included in this study. Genealogical and clinical data were obtained from a total of 623 individuals, including 126 affected by FAP. In 15 families, TTR genotyping was performed in all available relatives (n = 86), after informed written consent. Seven families did not consent for genetic testing, but agreed to provide clinical and genealogical data. Penetrance was estimated using a previously described method based on survival analysis and corrected for ascertainment bias. Results:, Mean age of onset in our sample was 34.5 years, with a significant earlier onset in males (31.1 vs. 35.9, P < 0.0001). The penetrance of FAP in our sample was estimated as 83% (95% CI: 66,99) after 60 years. Conclusion:, Our results provide new information on FAP in Brazilian patients and may be helpful in the genetic counseling of this population. [source]

Abstracts of the 8th Meeting of the Italian Peripheral Nerve Study Group: 46

JOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2003
L Padua
Traditional outcome assessment in neurological diseases has always been based on physician-derived and instrumental findings. Over the last two decades, clinical and public health researchers emphasized the need for a thorough evaluation of concepts such as Health Related Quality of Life (HRQoL) to study the impact of chronic illnesses and their treatments on the patient's life. The most frequent inherited neuropathy is Charcot-Marie-Tooth disease (CMT). CMT Patients develop progressive weakness and sensory disturbances, becoming sometimes severely disabled even at very young age. In CMT clinic, neurophysiologic, pathologic and genetic evaluation, are considered fundamental to assess nerve involvement and diagnose, but how these findings are related to HRQoL and disability is not assessed. We propose a prospective follow-up (24,30 months) of CMT patients with multiple measurements of CMT. Besides conventional clinic, pathologic, neurophysiologic and genetic measurements we adopt validated patient-oriented measurements to assess HRQoL and disability. Aims of the study are: 1) to assess HRQoL and disability of CMT patients in a wide and well-represented sample and to evaluate the relationships between conventional parameters and the patient's perception of his own HRQoL and disability; 2) to evaluate natural history of HRQoL and disability in CMT, and to evaluate the predictive value of phenotype, genetic picture, neurophysiological and pathological pattern 3) to develop a national network and a database on CMT disease (this aim includes the standardization, based on a consensus validation process, of the most used terms and measurements in CMT and the development of a database software). In a preliminary reunion, the authors developed a dedicated database for patients affected by CMT. Details about this database will be presented. [source]

Antiprogesterone therapy uncouples axonal loss from demyelination in a transgenic rat model of CMT1A neuropathy

ANNALS OF NEUROLOGY, Issue 1 2007
Gerd Meyer zu Horste MD
Objective Charcot,Marie,Tooth disease (CMT) is the most common inherited neuropathy, and a duplication of the Pmp22 gene causes the most frequent subform CMT1A. Using a transgenic rat model of CMT1A, we tested the hypothesis that long-term treatment with anti-progesterone (Onapristone) reduces Pmp22 overexpression and improves CMT disease phenotype of older animals, thereby extending a previous proof-of-concept observation in a more clinically relevant setting. Methods We applied placebo-controlled progesterone-antagonist therapy to CMT rats for 5 months and performed grip-strength analysis to assess the motor phenotype. Quantitative Pmp22 RT-PCR and complete histological analysis of peripheral nerves and skin biopsies were performed. Results Anti-progesterone therapy significantly increased muscle strength and muscle mass of CMT rats and reduced the performance difference to wildtype rats by about 50%. Physical improvements can be explained by the prevention of axon loss. Surprisingly, the effects of anti-progesterone were not reflected by improved myelin sheath thickness. Electrophysiology confirmed unaltered NCV, but less reduced CMAP recordings in the treatment group. Moreover, the reduction of Pmp22 mRNA, as quantified in cutaneous nerves, correlated with the clinical phenotype at later stages. Interpretation Progesterone-antagonist treatment. Pmp22 overexpression to a degree at which the axonal support function of Schwann cells is better maintained than myelination. This suggests that axonal loss in CMT1A is not caused by demyelination, but rather by a Schwann cell defect that has been partially uncoupled by anti-progesterone treatment. Pmp22 expression analysis in skin may provide a prognostic marker for disease severity and for monitoring future clinical trials. Ann Neurol 2007;61:61,72 [source]