Charcot-Marie-Tooth X type 1 (CMTX1) is caused by mutations in the connexin 32 gene (Cx32) on the X chromosome. Electrophysiologically, CMTX1 is usually associated with intermediate slowing of conduction velocities and severe impairments in male patients. In addition, patients with CMTX1 rarely present conduction block and temporal dispersion, which are characteristic findings in acquired demyelinating neuropathy. We report herein, for the first time in Korea, two patients with Cx32 mutations who exhibited unusual electrophysiological findings.
Charcot-Marie-Tooth Disease* ; Humans ; Korea ; Male ; X Chromosome

Charcot-Marie-Tooth disease (CMT) is the most common form of hereditary neuropathy with significant clinical and genetic heterogeneity. So far 28 genes have been cloned. The main clinical manifestations of CMT include progressive distal muscle wasting and weakness, impaired distal sensation, and diminishing or loss of tendon reflex. Patients may be classified into demyelinating type (CMT1) and axonal type (CMT2) according to electrophysiological and pathological characteristics. Establishment of a standard diagnostic procedure based on clinical, electrophysiological and pathological findings will enable accurate diagnosis in most CMT patients and provide guidance for gene consulting and prognosis.
Charcot-Marie-Tooth Disease ; classification ; diagnosis ; genetics ; Humans

Charcot-Marie-Tooth disease type 1A (CMT1A) is associated with duplication of chromosome 17p11.2-p12, whereas hereditary neuropathy with liability to pressure palsies (HNPP), which is an autosomal dominant neuropathy showing characteristics of recurrent pressure palsies, is associated with 17p11.2-p12 deletion. An altered gene dosage of PMP22 is believed to the main cause underlying the CMT1A and HNPP phenotypes. Although CMT1A and HNPP are associated with the same locus, there has been no report of these two mutations within a single family. We report a rare family harboring CMT1A duplication and HNPP deletion.
Charcot-Marie-Tooth Disease ; Gene Dosage ; Humans ; Paralysis ; Phenotype

Mutations of the CMT genes develop a variety of distinct phenotypes. Cx32 gene mutations cause the X-linked form of CMT disease, and mutations in EGR2 are associated with CMT type 1, DSS, and congenital hypomyelination neuropathy. Her parents, grandmother and sister did not show the V136A mutation in Cx32. We report the first CMT patient with EGR2 and Cx32 mutations.
Charcot-Marie-Tooth Disease ; Humans ; Parents ; Phenotype ; Siblings

Charcot-Marie-Tooth Disease ; Child, Preschool ; Humans ; Male

No abstract available.
Amyotrophic Lateral Sclerosis* ; Charcot-Marie-Tooth Disease* ; China* ; Pedigree*

Humans ; Charcot-Marie-Tooth Disease/complications* ; Hoarseness/etiology*

We report data on 2 members of a family affected by a dominantly inherited disorder closely resembling Roussy-Levy syndrome(RLS) Electrophysiological findings showed a marked decrease of motor and sensory conduction velocities and mild neurogenic damage. Light and electron microscopy of sural nerve biopsy showed a hypertrophic neuropathy with diffuse onion-bulb formations and marked decrease of large size fibers. Teased fiber preparations revealed reduced internodal lengths and segmental demyelination. The hypothesis that RLS is not a disease entity but a hypertrophic-type of Charcot-Marie Tooth disease with essential tremor(HMSN type 1) is strongly supported.
Biopsy ; Charcot-Marie-Tooth Disease* ; Demyelinating Diseases ; Humans ; Microscopy, Electron ; Sural Nerve ; Tooth Diseases

BACKGROUND AND PURPOSE: Charcot-Marie-Tooth disease (CMT) type 1A (CMT1A) is the demyelinating form of CMT that is significantly associated with PMP22 duplication. Some studies have found that the disease-related disabilities of these patients are correlated with their compound muscle action potentials (CMAPs), while others have suggested that they are related to the nerve conduction velocities. In the present study, we investigated the correlations between the disease-related disabilities and the electrophysiological values in a large cohort of Korean CMT1A patients. METHODS: We analyzed 167 CMT1A patients of Korean origin with PMP22 duplication using clinical and electrophysiological assessments, including the CMT neuropathy score and the functional disability scale. RESULTS: Clinical motor disabilities were significantly correlated with the CMAPs but not the motor nerve conduction velocities (MNCVs). Moreover, the observed sensory impairments matched the corresponding reductions in the sensory nerve action potentials (SNAPs) but not with slowing of the sensory nerve conduction velocities (SNCVs). In addition, CMAPs were strongly correlated with the disease duration but not with the age at onset. The terminal latency index did not differ between CMT1A patients and healthy controls. CONCLUSIONS: In CMT1A patients, disease-related disabilities such as muscle wasting and sensory impairment were strongly correlated with CMAPs and SNAPs but not with the MNCVs or SNCVs. Therefore, we suggest that the clinical disabilities of CMT patients are determined by the extent of axonal dysfunction.
Action Potentials ; Axons ; Charcot-Marie-Tooth Disease ; Cohort Studies ; Humans ; Muscles ; Neural Conduction

BACKGROUND: Mitofusin 2 (MFN2) is a membrane protein and is an essential component of mitochondrial fusion machinery. Mitochondrial fusion is essential for various biological functions in mammalian cells. Thus mutations in MFN2 are the underlying cause of Charcot-Marie-Tooth neuropathy type 2A (CMT2A). However, there has been no reports investigating the MFN2 genes in Korean CMT patients. Therefore, we investigated to find the clinical and genetic characteristics in Korean patients with the MFN2 gene mutation. METHODS: We examined the mutations of the MFN2 gene in 137 Korean CMT families. According to criteria from the European CMT consortium, CMT2 was 45 families. Mutations were confirmed by both strands sequencing. Nerve conduction studies were carried out in CMT patients having each mutation. RESULTS: Eight pathogenic mutations were found in 10 families. Six mutations (Leu92Pro, Gly127Asp, His165Arg, Ser263Pro, Arg364Trp, Met376Thr) were determined to be novel, and those were not detected in the 100 healthy controls. A de novo missense mutation was found in three CMT families (30%). The frequency of the MFN2 mutation was 22.2%, which was higher than those found in the Cx32 mutation. In CMT2A, the frequencies with early age at onset (<10 years) and flat feet were 46.2%. CONCLUSIONS: We found MFN2 mutations in patients with sporadic or dominantly inherited CMT. In the majority of cases with CMT type 2, the axonal neuropathy, may be due to MFN2 mutations.
Axons ; Charcot-Marie-Tooth Disease ; Flatfoot ; Humans ; Membrane Proteins ; Mitochondrial Dynamics ; Mutation, Missense ; Neural Conduction