Brain : a journal of neurology
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Charcot-Marie-Tooth disease type 1A is the most common inherited neuropathy and is caused by duplication of chromosome 17p11.2 containing the peripheral myelin protein-22 gene. This disease is characterized by uniform slowing of conduction velocities and secondary axonal loss, which are in contrast with non-uniform slowing of conduction velocities in acquired demyelinating disorders, such as chronic inflammatory demyelinating polyradiculoneuropathy. Mechanisms responsible for the slowed conduction velocities and axonal loss in Charcot-Marie-Tooth disease type 1A are poorly understood, in part because of the difficulty in obtaining nerve samples from patients, due to the invasive nature of nerve biopsies. ⋯ Our study demonstrates that skin biopsy can reveal pathological and molecular architectural changes that distinguish inherited from acquired demyelinating neuropathies. Uniformly shortened internodal length in Charcot-Marie-Tooth disease type 1A suggests a potential developmental defect of internodal lengthening. Intra-axonal accumulation of mitochondria provides new insights into the pathogenesis of axonal degeneration in Charcot-Marie-Tooth disease type 1A.
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Idiopathic rapid eye movement sleep behaviour disorder is an important risk factor in the development of Parkinson's disease. Numerous potential predictive markers of Parkinson's disease may present before motor symptoms emerge, but testing of these markers in rapid eye movement sleep behaviour disorder has been performed only in small studies. There has been no comparison of markers between patients with idiopathic rapid eye movement sleep behaviour disorder and Parkinson's disease, and between men and women. ⋯ Other than slightly better performances among women in the Purdue Peg Board, there was no difference in any measure between men and women, suggesting similar pathogenic processes underlying rapid eye movement sleep behaviour disorder. Patients with idiopathic rapid eye movement sleep behaviour disorder demonstrate abnormalities in numerous potential markers of neurodegenerative disease--these markers are heterogeneous, generally correlate with each other and occur equally in men and women. Although these abnormalities are usually intermediate between control values and Parkinson's patients, autonomic dysfunction and colour vision appear to be more linked to rapid eye movement sleep behaviour disorder status than Parkinson's disease, suggesting a unique pathophysiology of these abnormalities.