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At least 415 records · Page 23Linked to original sources
PubMed1985

X-linked dominant Charcot-Marie-Tooth disease: suggestion of linkage with a cloned DNA sequence from the proximal Xq.

A large kindred with the X-linked dominant form of peroneal muscular atrophy (Charcot-Marie-Tooth disease) was analyzed for individual variation in the length of DNA fragments after restriction endonuclease digestion. A systematic search was performed for linkage with a series of cloned single-copy DNA sequences of known regional assignment to the human X chromosome. Close linkage was found with the pDP34 probe (DXYS1 locus, Xq13-q21), suggesting that the gene responsible for the disease is located on the proximal long arm of the X chromosome.

Charcot-Marie-Tooth Disease↗
PubMed2005

[Identification of a new genetic entity in the form of an autosomal dominant axonal Charcot-Marie-Tooth disease associated with periodic paralyses and pyramidal syndrome].

We report the clinical and genetic linkage analysis of eight affected patients suffering from axonal form of Charcot-Marie-Tooth disease (CMT2) with periodic paralyses and pyramidal feature. The inheritance is autosomal dominant. It was characterized by onset between the first and the second decade, distal weakness and atrophy of lower limbs. Four patients showed deep sensory loss; a periodic paralyses were also present in four patients. Genetic linkage excluded all known loci of CMT2 and other loci of clinical distinctive feature. Exclusion of these loci demonstred the distinctive phenotype of this family and assess the identification of a new genetic form.

Adolescent↗
PubMed1997

Molecular and pathological studies in Charcot-Marie-Tooth disease 1A.

We analyzed a 1.5-Mb duplication of the p11.2-12 region of chromosome 17, including the PMP-22 gene (CMT1A duplication), seven families with Charcot-Marie-Tooth disease type I (CMT I) and six sporadic patients with suspected CMT I by Southern blot analysis. In order to detect the CMT 1A duplication, probe pVAW409R3a, probe PMP-22 cDNA and reference probe SF85 were used for Southern hybridization. In six out of seven families with CMT I, CMT1A duplication was identified. One of six sporadic CMT patients had CMT1A duplication. The probe pVAW4O9R3a was more informative than PMP-22 cDNA and SF85 for detecting CMT1A duplication. In pathological study of biopsied sural nerve, thickened myelin sheath was observed in some myelinated fibers in patients with CMT1A duplication.

Adolescent↗
PubMed1993

Origin of the de novo duplication in Charcot-Marie-Tooth disease type 1A: unequal nonsister chromatid exchange during spermatogenesis.

A 1.5 Mb duplication within 17p11.2 is the major mutation causing both autosomal dominant and sporadic Charcot-Marie-Tooth disease type 1A (CMT1A). An independent origin for the mutation in each family has been postulated. The proposed genetic mechanism causing the CMT1A duplication is unequal nonsister chromatid exchange at meiosis (unequal crossing-over). We studied the parental origin of the duplication in nine genetically sporadic CMT1A patients and demonstrated that in all cases the mutation was the product of an unequal nonsister chromatid exchange during spermatogenesis. The fact that only paternal de novo duplications were observed in the sporadic CMT1A patients suggests that male specific factors may be operating during spermatogenesis that either help forming the duplication and/or stabilize the duplicated chromosome.

Blotting, Southern↗
PubMed1996

Connexin 32 mutations from X-linked Charcot-Marie-Tooth disease patients: functional defects and dominant negative effects.

We have characterized the function of connexin (Cx) 32 gene mutations found in X-linked dominant Charcot-Marie-Tooth disease with respect to their ability to form functional gap junctions among themselves and to inactivate wild-type Cx32 by a dominant negative mechanism. We prepared four types of Cx32 mutant cDNAs and transfected them into HeLa cells, which do not show detectable levels of gap junctional intercellular communication (GJIC), nor expression of any connexins examined. Cells transfected with the wild-type Cx32 gene, but not those transfected with three different base substitution mutations (i.e. Cys 60 to Phe, Val 139 to Met, and Arg 215 to Trp), restored GJIC. Unexpectedly, in cells transfected with a nonsense mutant at codon 220, there was also restored GJIC. When we double-transfected these mutant constructs into the HeLa cells that had already been transfected with the wild-type Cx32 gene and thus were GJIC proficient, three base substitution mutants inhibited GJIC, suggesting that these three mutants can eliminate the function of wild-type Cx32 in a dominant negative manner. The nonsense mutation at codon 220 did not show such a dominant negative effect. Since both mutant and wild-type Cx32 mRNAs were detected, but only poor Cx32 protein expression at cell-cell contact areas was observed in the double transfectants, it is suggested that certain mutants form nonfunctional chimeric connexons with wild-type connexins, which are not properly inserted into the cytoplasmic membrane.

Amino Acid Sequence↗
PubMed1992

[An autopsy case of neuronal type Charcot-Marie-Tooth disease (HMSN type II) with nerve deafness and psychiatric symptoms].

The clinical and pathological findings of a 41-year-old male patient with atypical Charcot-Marie-Tooth disease were reported. There were 3 cases of subarachnoid haemorrhage, 2 nerve deafness and 2 hereditary motor and sensory neuropathy (HMSN) in his family. He had suffered from progressive nerve deafness since 5 years old and gait disturbance since 37 years old. He had been admitted to the psychiatric hospital 3 times because of hallucinatory-delusional state and behavior abnormalities. Neurological examinations at 39 years old revealed that he had mental deterioration (IQ 66), nerve deafness, diffuse muscle atrophy, most marked distally, sensory disturbance, areflexia, positive Romberg's sign, orthostatic hypotension, dysphagia and slurred speech. MCV of median nerve was 27.8 m/sec, and SCV was not evoked. EEG revealed nonspecific dysfunction of the brain. He died of ileus-like condition at 41 years old. General autopsy showed haemorrhagic infarction of the jejunum and ileum due to compression of the superior mesenteric artery and vein by an adhesion band of connective tissue formed after previous appendectomy. Neuropathological examinations revealed axonal degeneration and loss of myelinated fibers with schwannosis of anterior and posterior spinal nerve roots as well as peripheral nerves. The posterior roots were more severely affected than the anterior ones. Ganglion cells of the posterior root ganglia showed remarkable degeneration and loss. There was severe degeneration of the posterior columns, especially in the gracilis, of the spinal cord. Nerve cells in the anterior horns and Clarke's columns also displayed conspicuous atrophy or central chromatolysis followed by gliosis. There was slight degeneration of the posterior spinocerebellar tracts.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2005

Current Therapy for Charcot-Marie-Tooth Disease.

Charcot-Marie-Tooth (CMT), or heritable peripheral neuropathies, is among the most frequent genetic neuromuscular disorders, with a prevalence of approximately 1:2500. Since 1991, remarkable advances have occurred in determining the precise genetic cause of many forms of CMT and in generating animal models of many of these disorders. However, these advances have not yet resulted in cures for CMT. Recently, potential treatments for the most common form of CMT, CMT-1A, have been shown in rodent models of the disorder. Treatment with onapristone, a progesterone antagonist, has improved the neuropathy of the CMT-1A rat. Treatment with large doses of ascorbic acid (vitamin C) has improved the neuropathy of the CMT-1A mouse. Multicentric trials with ascorbic acid are likely to start in the near future to assess if vitamin C supplementation is effective and what is the dosage required in humans to improve neurologic disability. Because of potential side effects with antiprogesterone therapy, particularly in women of child- bearing age, research is actively proceeding with progesterone antagonists to develop safe medications that also can be used in clinical trials of CMT-1A. Although no cures are available for CMT, there are many important treatments available for patients with CMT that can improve their quality of life and help them maintain their independence. Some of these therapies involve physiatry and orthopedic surgery. Others involve pain management. Lastly, there are potential concerns about medications or lifestyle issues that may exacerbate CMT. All of these issues will be discussed.

Journal Article↗
PubMed2002

X-linked Charcot-Marie-Tooth disease caused by a novel point mutation in the connexin-32 gene.

We report the clinical and electrophysiological findings of a patient with X-linked Charcot-Marie-Tooth disease and a novel point mutation in the connexin-32 gene. A 31-year-old man presented with a 5 year history of progressive imbalance and distal weakness in his legs. Electrophysiological studies confirmed an asymmetric, predominantly axonal sensorimotor neuropathy with some demyelinating features. Genetic testing revealed a G/A transition (Ala40Thr) in a conserved transmembrane region of the connexin-32 gene.

Adult↗
PubMed2004

Clinical and genetic description of a family with Charcot-Marie-Tooth disease type 1B from a transmembrane MPZ mutation.

Mutations in the myelin protein zero gene (MPZ) are associated with certain demyelinating neuropathies, and in particular with Charcot-Marie-Tooth disease type 1B (CMT1B), Dejerine-Sottas syndrome, and congenital hypomyelination. MPZ mutations affecting the protein's transmembrane domain are generally associated with more severe phenotypes. We describe a family with mild CMT1B associated with a transmembrane MPZ mutation. Sequence analysis identified a G-to-C transversion at nucleotide 1064, predicting a glycine-to-arginine substitution in codon 163 (G163R) of MPZ. This report furthers the understanding of the clinical and electrophysiological manifestations of MPZ mutations.

Charcot-Marie-Tooth Disease↗
PubMed2001

A novel missense mutation in the early growth response 2 gene associated with late-onset Charcot--Marie--Tooth disease type 1.

A novel mutation (Arg381Cys) in the second zinc-finger domain of early growth response 2 (EGR2) was identified in a late-onset Charcot--Marie--Tooth disease type 1 (CMT1) patient. This patient had initial symptoms of numbness and weakness in the leg at age 59, and a median nerve motor conduction velocity of 27 m/s. A sural nerve biopsy showed a severe loss of myelinated fibers with numerous onion bulbs. This is the first report of the EGR2 mutation presenting a late onset of CMT1 phenotype. Its mutation was a different amino acid substitution at codon 381 (Arg381His) which demonstrated congenital hypomyelinating neuropathy or early-onset CMT1. This report suggests that the EGR2 mutation represents divergent phenotypes at codon 381, which may be a mutation hotspot.

Aged↗
PubMed1984

Neuronal type of Charcot-Marie-Tooth disease with a syndrome of continuous motor unit activity.

The clinical, genetic and electrophysiological study of 3 patients with an association of a neuronal form of Charcot-Marie-Tooth Disease (CMTD) with a syndrome of continuous motor unit activity (CMUA) are reported, with light and electron microscopy of muscle and sural nerve biopsies in 2 patients. The unusual clinical features of CMTD were associated with fasciculation, cramps, myokymia, impaired muscular relaxation and percussion myotonia with their electromyographic (EMG) correspondent, responsive to valproic acid (VPA) therapy. In Case 3, an important muscle hypertrophy which was confirmed by morphometric data, was noted in addition. Nerve biopsy and electrophysiological findings indicated that axonal degeneration with secondary demyelination and remyelination underlie the hereditary motor and sensory neuropathy (HMSN) in our patients. The hyperexcitability and hyperactivity of peripheral motor axons probably induced by the hereditary neuropathy may, in this instance, be the causative condition of the syndrome of CMUA in our patients.

Adolescent↗
PubMed1998

Charcot-Marie-Tooth disease type 1A with 17p duplication in infancy and early childhood: a longitudinal clinical and electrophysiologic study.

OBJECTIVE: We describe longitudinal clinical and electrophysiologic evaluation of Charcot-Marie-Tooth disease type 1A (CMT-1A) in infancy and early childhood. BACKGROUND: The clinical picture and electrophysiologic evaluation of CMT-1A during the age of nerve conduction maturation have not been documented. DESIGN/METHODS: Twenty at-risk children from six unrelated CMT-1A families were examined in the first 5 years of life. Initial ages were 1 month to 4 years (mean, 1.5 years) and final ages 4 to 19 years (mean, 9 years). All subjects had two or more motor and sensory conduction velocities (MCV and SCV), corrected distal motor latencies (DML), and F-waves. RESULTS: Twelve children were affected. Initially, two of these (17%) had symptoms, whereas five (42%) were symptomatic at the end. Numbers of abnormal examinations at the beginning was six (50%) and at conclusion was 10 (83%). None of the patients were disabled. From 2 years of age, all affected children had abnormal MCV, SVC, F-waves, and DML. Prolonged DML was already present in the first months of life and preceded slowing of MCV in three cases. CONCLUSION: The electrophysiologic studies were concordant with the presence or absence of the CMT-1A DNA duplication. In most CMT-1A patients, symptoms appear in early childhood, although the florid clinical picture does not occur until the second decade of life. Serial electrophysiologic studies can detect the CMT-1A gene carrier in infancy.

Adolescent↗
PubMed1996

Construction of a mouse model of Charcot-Marie-Tooth disease type 1A by pronuclear injection of human YAC DNA.

Construction of animal models of human inherited diseases is particularly important for testing gene therapy approaches. Towards this end, we constructed a mouse model for Charcot-Marie-Tooth disease type 1A by pronuclear injection of a YAC containing the human PMP22 gene. In one transgenic line, the YAC DNA is integrated in about eight copies and the PMP22 gene is strongly expressed to give a peripheral neuropathy closely resembling the human pathology. The disorder is dominant, causes progressive weakness of the hind legs, and there is severe demyelination in the peripheral nervous system including the presence of onion bulb formations. This approach will be valuable for pathologies produced by over-expression of a gene including trisomy and amplification in cancer. Such models will be particularly useful for testing gene therapy approaches if the transgene is human.

Animals↗
PubMed2006

[Cloning to rule out 10 candidate genes located in chromosome 12q24 for Charcot-Marie-Tooth disease type 2L].

OBJECTIVE: To clone the disease-causing genes possibly existing in 6.8 cM distance between microsatellite markers D12S1720 and D12S1611 in chromosome 12q24 for Charcot-Marie-Tooth disease type 2L (CMT2L). METHODS: Ten positional and functional candidate genes were chosen among all known genes in this locus region by bioinformatics inqury. Mutation detection was performed by sequencing the exons and intron-exon junctions of the candidate genes. RESULTS: Eleven sequence variations, that included 5 heterozygous and 6 homozygous variations, were detected in the exons and flanking areas of the 10 candidate genes. All the variations showed no co-segregation with disease phenotype. CONCLUSION: Ten candidate genes(TAOK3, RAB35, RPLP0, PXN, RNF10, RHOF, VPS33A, RSN, DENR, RNP24) were ruled out as the disease-causing gene for CMT2L. Ten single nucleotide polymorphisms (SNP) were reported for the first time.

Base Sequence↗
PubMed2005

Medication-induced exacerbation of neuropathy in Charcot Marie Tooth disease.

Toxin or medication-induced worsening of preexisting peripheral neuropathy is a generally accepted but not well-studied phenomenon in humans. Drug-induced exacerbation of Charcot Marie Tooth disease (CMT) neuropathy is a common concern; a list of potential drugs to avoid is maintained by the CMT Association but with limited direct evidence or advice on relative risk. An extensive literature search for reported cases of drug effects in CMT patients found the vast majority concerned excessive vincristine toxicity in patients with undiagnosed demyelinating forms of CMT, many after 1 or 2 doses. The CMT North American database was also queried for all drug-related effects. All but one drug cited as worsening neuropathy was present on a compiled inclusive list. These results and other available evidence were used to develop a revised risk stratified list for CMT patients and clinicians to consult prior to discussing risk to benefit ratios and making treatment decisions.

Antineoplastic Agents, Phytogenic↗
PubMed2006

Schwann cells and the pathogenesis of inherited motor and sensory neuropathies (Charcot-Marie-Tooth disease).

Over the last 15 years, a number of mutations in a variety of genes have been identified that lead to inherited motor and sensory neuropathies (HMSN), also called Charcot-Marie-Tooth disease (CMT). In this review we will focus on the molecular and cellular mechanisms that cause the Schwann cell pathologies observed in dysmyelinating and demyelinating forms of CMT. In most instances, the underlying gene defects alter primarily myelinating Schwann cells followed by secondary axonal degeneration. The first set of proteins affected by disease-causing mutations includes the myelin components PMP22, P0/MPZ, Cx32/GJB1, and periaxin. A second group contains the regulators of myelin gene transcription EGR2/Krox20 and SOX10. A third group is composed of intracellular Schwann cells proteins that are likely to be involved in the synthesis, transport and degradation of myelin components. These include the myotubularin-related lipid phosphatase MTMR2 and its regulatory binding partner MTMR13/SBF2, SIMPLE, and potentially also dynamin 2. Mutations affecting the mitochondrial fission factor GDAP1 may indicate an important contribution of mitochondria in myelination or myelin maintenance, whereas the functions of other identified genes, including NDRG1, KIAA1985, and the tyrosyl-tRNA synthase YARS, are not yet clear. Mutations in GDAP1, YARS, and the pleckstrin homology domain of dynamin 2 lead to an intermediate form of CMT that is characterized by moderately reduced nerve conduction velocity consistent with minor myelin deficits. Whether these phenotypes originate in Schwann cells or in neurons, or whether both cell types are directly affected, remains a challenging question. However, based on the advances in systematic gene identification in CMT and the analyses of the function and dysfunction of the affected proteins, crucially interconnected pathways in Schwann cells in health and disease have started to emerge. These networks include the control of myelin formation and stability, membrane trafficking, intracellular protein sorting and quality control, and may extend to mitochondrial dynamics and basic protein biosynthesis.

Animals↗
PubMed1983

Visual evoked potential abnormalities in Charcot-Marie-Tooth disease and comparison with Friedreich's ataxia.

Pattern-reversal visual evoked potentials (VEPs), recorded in 15 visually asymptomatic patients fulfilling the clinical and electrophysiological criteria of Charcot-Marie-Tooth disease (CMTD), were abnormal in 5 and possibly abnormal in another 3. Five patients showed a prolongation of P100 latency, one a reduction of amplitude and one a possibly abnormal "scotomatous" waveform. In 9 cases abnormalities were detected on neuro-ophthalmological examination. These were poorly correlated with VEP abnormalities, except for patients with 2 or more clinical eye signs. Relative central scotomata were found in the patient with an abnormal waveform. VEP abnormalities, where present, were usually fairly comparable in the 2 eyes. In comparison with a group of Friedrich's ataxia cases there was a lower overall incidence of VEP abnormalities in CMTD, but little to suggest a qualitative difference in the nature of the visual pathway pathology. All 4 patients with unequivocally abnormal VEPs had experienced atypical symptoms suggestive of CNS involvement. In none of these was it possible to sustain an alternative diagnosis. It is concluded that a minor degree of visual pathway involvement may be present in many CMTD cases, in spite of the fact that optic atrophy is only rarely reported, and that the VEP latency may reflect the degree to which other parts of the CNS are involved.

Adolescent↗
PubMed2000

Charcot-Marie-Tooth disease type 1A (CMT1A) and hereditary neuropathy with liability to pressure palsies (HNPP): reliable detection of the CMT1A duplication and HNPP deletion using 8 microsatellite markers in 2 multiplex PCRs.

Charcot-Marie-Tooth disease (CMT) and hereditary neuropathy with liability to pressure palsies (HNPP) are the most frequent inherited disorders of the peripheral nervous system. They are clinically and genetically heterogeneous. A submicroscopic tandem duplication of 1. 5 Mb in chromosome 17p11.2-12 comprising the PMP22 gene is found in 70.7% of autosomal dominant Charcot-Marie-Tooth type 1 (CMT1) patients. A reciprocal deletion is found in 87.6% of HNPP patients. The size of the typical CMT1A duplication is too small for classical cytogenetics and the whole region including the CMT1A-REP elements is sometimes too complex for a single DNA analysis method. We present results of a multiplex PCR of 8 microsatellite markers with multicolour fluorescence primer labelling followed by fragment analysis on an ABI 310 Prism analyzer to simplify the diagnostic procedure. Results for 24 patients can be obtained within 24 h. This method was applied on 92 DNA samples of unrelated patients carrying a typical CMT1A duplication previously confirmed by two colour fluorescence in situ hybridization (FISH, probe c132G8) and EcoRI/SacI Southern blotting (probe pLR7.8). Three alleles of three different sizes were clearly detected at least once in 88 of them (95.6%). Subsequently this analysis was applied on 312 Czech patients and revealed a CMT1A/HNPP rearrangement in 109 out of them.

Alleles↗