Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0031117 (peripheral neuropathy)
 10,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this study we describe four patients from the same kindred who were affected by an autosomal-dominantly inherited peripheral neuropathy. They presented an unusual combination of clinical, electrophysiological, and pathological findings in association with a new mutation of the PMP22 gene. Clinically, three patients had carpal tunnel syndrome symptoms and one patient had late-onset peroneal atrophy. Motor and sensory nerve conduction velocities were reduced without focal slowing at entrapment sites. Nerve biopsy disclosed diffuse hypomyelination with focal thickening of the myelin sheath in some fibers. Sequence analysis of the PMP22 gene showed a single-nucleotide deletion (227delG) in the affected patients. This mutation, which has not been reported previously, leads to an open reading frame shift and probably to a truncated and unstable PMP22 protein. We conclude that this novel 227delG mutation of PMP22 gives a mild form of hereditary neuropathy with liability to pressure palsy with atypical clinical and electrophysiological findings.
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PMID:A new single-nucleotide deletion of PMP22 in an HNPP family without recurrent palsies. 1864 76

Charcot-Marie-Tooth disease (CMT), also called hereditary motor and sensory neuropathy (HMSN), is the most common inherited peripheral neuropathy, comprised by a group of genetically heterogeneous disorders that share clinical characteristics of progressive distal muscle weakness and atrophy, foot deformities, distal sensory loss, and depressed tendon reflexes. It can be categorized according to its electrophysiological or pathological features, transmission patterns, age of disease onset, and molecular pathology. CMT type 1 (CMT1; MIM 118200) is a group of autosomal dominant-inherited demyelinating neuropathies with a disease onset at or after childhood. Five different subtypes have been identified based on different causative genes. Among them, CMT1A (MIM #118220) is most common and is usually associated with a duplication of a 1.5-Mb region on chromosome 17p11.2, which includes peripheral myelin protein 22 gene (PMP22; MIM *601097). Currently, there is no cure or obviously effective disease-modifying treatment for CMT. Two potential effective therapeutic agents for CMT1A were investigated recently. One is ascorbic acid and another is neurotrophin-3 (NT-3), an important component of the Schwann cell autocrine survival loop. Early diagnosis can facilitate CMT patients to modify their life styles timely for minimizing nerve injury to delay or avoid disability. Molecular diagnosis of CMT can provide the basis for appropriate genetic counseling and further CMT research.
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PMID:[Charcot-Marie-Tooth disease]. 1897 29

Peripheral neuropathies include a wide range of pathological disorders characterized by damage of peripheral nerves. Among them, peripheral hereditary neuropathies are a group of frequent illnesses and early evolution. They have been named hereditary motor and sensory neuropathy (HMSN) or peripheral hereditary neuropathies type Charcot-Marie-Tooth (CMT). The most frequent types are CMT1, CMT2 and CMTX. Approximately 70% of the cases correspond to subtype CMT1A, associated with tandem duplication of a 1.5 Mb DNA fragment on chromosome 17p11.2-p12 that codifies the peripheral myelin protein PMP22. So far, there five different types of CMT (1,2,3,4,X) with approximately 32 subtypes, associated with more than 30 genes. Have been reported genetic heterogeneity and expression variability of the illness makes it necessary to carry on diagnostic strategies that integrate clinical study for determining genetic clinical history, family history, complete physical exploration, muscular strength, physical deformities, reflexes and sensitivity, and molecular studies allow detection of different types of mutations and help establish a correct diagnosis and an adequate genetic counseling.
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PMID:[Diagnosis of the peripheral hereditary neuropathies and its molecular genetics]. 1897 92

A 56-year-old male with recurrent painless focal neuropathies and a family history of peripheral neuropathy of unknown etiology presented with progressively worsening of impaired sensations and weakness in his lower extremities. His initial electrodiagnostic evaluation was suggestive of severe sensory and motor peripheral polyneuropathy. The genetic testing was performed for familial causes of peripheral neuropathy as there was a family history of peripheral neuropathy of unknown etiology. The patient was found to have 1.5-Mb deletion in the PMP22 gene which was confirmatory of hereditary neuropathy with liability to pressure palsies (HNPP). He developed progressive upper and lower extremity weakness, bulbar dysfunction and widespread fasciculations during the course of his illness. He was subsequently diagnosed with amyotrophic lateral sclerosis (ALS). This is the second reported case of HNPP associated with ALS. We discuss significant clinical and electrodiagnostic findings of this interesting case.
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PMID:Hereditary neuropathy with liability to pressure palsies and amyotrophic lateral sclerosis. 1923 16

Charcot Marie Tooth (CMT) syndrome is the most common hereditary peripheral neuropathy, with an incidence of about 1 in 2500. The subtype 1A (CMT1A) is caused by a tandem duplication of a 1.5-Mb region encompassing the PMP22 gene. Conventional short tandem repeat (STR) analysis can reveal this imbalance if a triallelic pattern, defining with certainty the presence of duplication, is present. In case of duplication with a biallelic pattern, it can only indicate a semiquantitative dosage of the fluorescence intensity ratio of the two fragments. In this study we developed a quantitative fluorescence-PCR using seven highly informative STRs within the CMT1A critical region that successfully disclosed or excluded the presence of the pathogenic imbalance in a cohort of 60 samples including 40 DNAs from samples with the CMT1A duplication previously characterized with two different molecular approaches, and 20 diagnostic samples from 10 members of a five-generation pedigree segregating CMT1A, 8 unrelated cases and 2 prenatal samples. The application of the quantitative fluorescence-PCR using STRs located in the critical region could be a reliable method to evaluate the presence of the PMP22 duplication for the diagnosis and classification of hereditary neuropathies in asymptomatic subjects with a family history of inherited neuropathy, in prenatal samples in cases with one affected parent, and in unrelated patients with a sporadic demyelinating neuropathy with clinical features resembling CMT (i.e., pes cavus with hammer toes) or with conduction velocities in the range of CMT1A.
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PMID:Quantitative fluorescence-polymerase chain reaction assay for the detection of the duplication of the Charcot Marie Tooth disease type 1A critical region. 2018 62

The X-linked form of Charcot-Marie-Tooth disease (CMTX) is the second most common form of this genetically heterogeneous inherited peripheral neuropathy. CMT1X is caused by mutations in the GJB1 gene. Most of the mutations causative for CMT1X are missense mutations. In addition, a few disease causative nonsense mutations and frameshift deletions that lead to truncated forms of the protein have also been reported to be associated with CMT1X. Previously, there have been reports of patients with deletions of the coding sequence of GJB1; however, the size and breakpoints of these deletions were not assessed. Here, we report five patients with deletions that range in size from 12.2 to 48.3 kb and that completely eliminate the entire coding sequence of the GJB1 gene, resulting in a null allele for this locus. Analyses of the breakpoints of these deletions showed that they are nonrecurrent and that they can be generated by different mechanisms. In addition to PMP22, GJB1 is the second CMT gene for which both point mutations and genomic rearrangements can cause a neuropathy phenotype, stressing the importance of CMT as a genomic disorder.
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PMID:GJB1/Connexin 32 whole gene deletions in patients with X-linked Charcot-Marie-Tooth disease. 2053 33

Rare copy number variations by the nonrecurrent rearrangements involving PMP22 have been recently suggested to be associated with CMT1A peripheral neuropathy. As a mechanism of the nonrecurrent rearrangement, replication-based fork stalling template switching (FoSTeS) by microhomology-mediated break-induced replication (MMBIR) has been proposed. We found three Korean CMT1A families with putative nonrecurrent duplication. The duplications were identified by microsatellite typing and applying a CGH microarray. The breakpoint sequences in two families suggested an Alu-Alu-mediated rearrangement with the FoSTeS by the MMBIR, and a two-step rearrangement of the replication-based FoSTeS/MMBIR and meiosis-based recombination. The two-step mechanism has still not been reported. Segregation analysis of 17p12 microsatellite markers and breakpoint junction analysis suggested that the nonrecurrent rearrangements are stably inherited without alteration of junction sequence; however, they may allow some alteration of the genomic contents in duplication across generations by recombination event. It might be the first study on the pedigree analysis of the large CMT1A families with nonrecurrent rearrangements. It seems that the exact mechanism of the nonrecurrent rearrangements in the CMT1A may have a far more complex process than has been expected.
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PMID:Inheritance of Charcot-Marie-Tooth disease 1A with rare nonrecurrent genomic rearrangement. 2119 43

Early onset hereditary motor and sensory neuropathies are rare disorders encompassing congenital hypomyelinating neuropathy with disease onset in the direct post-natal period and Dejerine-Sottas neuropathy starting in infancy. The clinical spectrum, however, reaches beyond the boundaries of these two historically defined disease entities. De novo dominant mutations in PMP22, MPZ and EGR2 are known to be a typical cause of very early onset hereditary neuropathies. In addition, mutations in several other dominant and recessive genes for Charcot-Marie-Tooth disease may lead to similar phenotypes. To estimate mutation frequencies and to gain detailed insights into the genetic and phenotypic heterogeneity of early onset hereditary neuropathies, we selected a heterogeneous cohort of 77 unrelated patients who presented with symptoms of peripheral neuropathy within the first year of life. The majority of these patients were isolated in their family. We performed systematic mutation screening by means of direct sequencing of the coding regions of 11 genes: MFN2, PMP22, MPZ, EGR2, GDAP1, NEFL, FGD4, MTMR2, PRX, SBF2 and SH3TC2. In addition, screening for the Charcot-Marie-Tooth type 1A duplication on chromosome 17p11.2-12 was performed. In 35 patients (45%), mutations were identified. Mutations in MPZ, PMP22 and EGR2 were found most frequently in patients presenting with early hypotonia and breathing difficulties. The recessive genes FGD4, PRX, MTMR2, SBF2, SH3TC2 and GDAP1 were mutated in patients presenting with early foot deformities and variable delay in motor milestones after an uneventful neonatal period. Several patients displaying congenital foot deformities but an otherwise normal early development carried the Charcot-Marie-Tooth type 1A duplication. This study clearly illustrates the genetic heterogeneity underlying hereditary neuropathies with infantile onset.
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PMID:Genetic spectrum of hereditary neuropathies with onset in the first year of life. 2184 Aug 89

Myelin insulates axons in the peripheral nervous system to allow rapid propagation of action potentials, and proper myelination requires the precise regulation of genes encoding myelin proteins, including PMP22. The correct gene dosage of PMP22 is critical; a duplication of PMP22 is the most common cause of the peripheral neuropathy Charcot-Marie-Tooth Disease (CMT) (classified as type 1A), while a deletion of PMP22 leads to another peripheral neuropathy, hereditary neuropathy with liability to pressure palsies. Recently, duplications upstream of PMP22, but not containing the gene itself, were reported in patients with CMT1A like symptoms, suggesting that this region contains regulators of PMP22. Using chromatin immunoprecipitation analysis of two transcription factors known to upregulate PMP22-EGR2 and SOX10-we found several enhancers in this upstream region that contain open chromatin and direct reporter gene expression in tissue culture and in vivo in zebrafish. These studies provide a novel means to identify critical regulatory elements in genes that are required for myelination, and elucidate the functional significance of non-coding genomic rearrangements.
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PMID:Distal enhancers upstream of the Charcot-Marie-Tooth type 1A disease gene PMP22. 2218 Apr 61

Charcot-Marie-Tooth disease type 1A (CMT1A) is a hereditary demyelinating peripheral neuropathy caused by the duplication of the PMP22 gene. Demyelination precedes the occurrence of clinical symptoms that correlate with axonal degeneration. It was postulated that a disturbed axon-glia interface contributes to altered myelination consequently leading to axonal degeneration. In this study, we examined the expression of MAG and Necl4, two critical adhesion molecules that are present at the axon-glia interface, in sural nerve biopsies of CMT1A patients and in peripheral nerves of mice overexpressing human PMP22, an animal model for CMT1A. We show an increase in the expression of MAG and a strong decrease of Necl4 in biopsies of CMT1A patients as well as in CMT1A mice. Expression analysis revealed that MAG is strongly upregulated during peripheral nerve maturation, whereas Necl4 expression remains very low. Ablating MAG in CMT1A mice results in separation of axons from their myelin sheath. Our data show that MAG is important for axon-glia contact in a model for CMT1A, and suggest that its increased expression in CMT1A disease has a compensatory role in the pathology of the disease. Thus, we demonstrate that MAG together with other adhesion molecules such as Necl4 is important in sustaining axonal integrity.
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PMID:An essential role of MAG in mediating axon-myelin attachment in Charcot-Marie-Tooth 1A disease. 2294 Jun 29


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