• Journal of Genetic Medicine
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• v.15 no.2
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• pp.107-109
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• 2018

X-linked Charcot-Marie-Tooth disease type 1 (CMTX1) is caused by the mutation in GJB1 gene, characterized by the transient central nervous system involvement and long standing peripheral polyneuropathy which does not fulfill the criteria of demyelination or axonopathy. We describe a 37-year-old man with progressive bilateral leg weakness since his early teen. He suffered transient right hemiparesis, followed by quadriparesis at 14 years of age. When we examined him at 37 years of age, he presented a distal muscle weakness on lower extremities with a sensory symptom. The nerve conduction study demonstrated a motor conduction velocity between 26 and 49 m/s. The whole exome sequencing revealed a novel variant c.136 G>A in GJB1. This report will raise awareness in this rare disease, which is frequently misdiagnosed early in its course.

• Annals of Clinical Neurophysiology
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• v.23 no.2
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• pp.130-133
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• 2021

X-linked Charcot Marie Tooth disease type 1 (CMTX1) is a clinically heterogenous X-linked hereditary neuropathy caused by mutation of the gene encoding gap junction beta 1 protein (GJB1). Typical clinical manifestations of CMTX1 are progressive weakness or sensory disturbance due to peripheral neuropathy. However, there have been some CMTX1 cases with accompanying central nervous system (CNS) manifestations. We report the case of a genetically confirmed CMTX1 patient who presented recurrent transient CNS symptoms without any symptom or sign of peripheral nervous system involvement.

• Annals of Clinical Neurophysiology
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• v.7 no.2
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• pp.65-74
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• 2005

Charcot-Marie-Tooth (CMT) disease was described by Charcot and Marie in France and, independently, by Tooth in England in 1886. CMT is the most common form of inherited motor and sensory neuropathy, and is a genetically heterogeneous disorder of the peripheral nervous system. Therefore, many genes have been identified as CMT-causative genes. Traditionally, subclassification of CMT have been divided into autosomal dominant inherited demyelinating (CMT1) and axonal (CMT2) neuropathies, X-linked neuropathy (CMTX), and autosomal recessive inherited neuropathy (CMT4). Recently, intermediate type (CMT-Int) with NCVs between CMT1 and CMT2 is considered as a CMT type. There are several related peripheral neuropathies, such as $D{\acute{e}}j{\acute{e}}rine$-Sottas neuropathy (DSN), congenital hypomyelination (CH), hereditary neuropathy with liability to pressure palsies (HNPP) and giant axonal neuropathy (GAN). Great advances have been made in understanding the molecular basis of CMT, and 17 distinct genetic causes of CMT have been identified. The number of newly discovered mutations and identified genetic loci is rapidly increasing, and this expanding list has proved challenging for physicians trying to keep up with the field. Identifying the genetic cause of inherited neuropathies is often important to determine at risk family members as well as diagnose the patient. In addition, the encouraging studies have been published on rational potential therapies for the CMT1A. Now, we develop a model of how the various genes may interact in the pathogenesis of CMT disorder.

• Journal of Life Science
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• v.18 no.6
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• pp.764-769
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• 2008

Mutations in the human connexin 32 (Cx32) gene are responsible for X-linked Charcot-Marie-Tooth (CMTX) disease. Although over 300 different mutations have been identified the detailed molecular etiology of CMTX disease is poorly understood. Several studies reported that connexin membrane channels share most biophysical properties with their parental gap junction channels. In this study, two connexin mutant membrane channels (one mutant channel called the M34T channel in which the methionine residue at the $34^{th}$ position of the Cx32 protein is replaced with threonine residue and the other mutant channel called the T86C channel in which the threonine residue at the $86^{th}$ position is replaced with cysteine residue) associated with CMTX mutations were characterized at the single-channel level instead of using mutant gap junction channels. The biophysical properties of the M34T channel were very similar to those of the gap junction channel formed by M34T mutation. In addition, the mutant membrane channel study revealed the reversal of the gating polarity, the loss of fast gating and the gain of slow gating. The T86C channel also behaves like its parental wild type Cx32 membrane channel. Taken together, these results suggest that a study using connexin membrane channels is useful to characterize CMTX mutants.