Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026850 (muscular dystrophy)
 5,870 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Epidermolysis bullosa simplex with muscular dystrophy (EBS-MD, MIM 226670) is caused by plectin defects. We performed mutational analysis and immunohistochemistry using EBS-MD (n = 3 cases) and control skeletal muscle to determine pathogenesis. Mutational analysis revealed a novel homozygous plectin-exon32 rod domain mutation (R2465X). All plectin/HD1-121 antibodies stained the control skeletal muscle membrane. However, plectin antibodies stained the cytoplasm of type II control muscle fibers (as confirmed by ATPase staining), whereas HD1-121 stained the cytoplasm of type I fibers. EBS-MD samples lacked membrane (n = 3) but retained cytoplasmic HD1-121 (n = 1) and plectin staining in type II fibers (n = 3). Ultrastructurally, EBS-MD demonstrated widening and vacuolization adjacent to the membrane and disorganization of Z-lines (n = 2 of 3) compared to controls (n = 5). Control muscle immunogold labeling colocalized plectin and desmin to filamentous bridges between Z-lines and the membrane that were disrupted in EBS-MD muscle. We conclude that fiber-specific plectin expression is associated with the desmin-cytoskeleton, Z-lines, and crucially myocyte membrane linkage, analogous to hemidesmosomes in skin.
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PMID:Plectin defects in epidermolysis bullosa simplex with muscular dystrophy. 1696 86

The efficient treatment of hereditary disorders, especially of those caused by dominant-negative mutations still remains an obstacle to be overcome. Allele specificity is a critical aspect that must be addressed by silencing therapies such as small interfering RNA, which has the potential risk of also reducing expression of the normal allele. To overcome this hurdle, we used spliceosome-mediated RNA trans-splicing (SMaRT) to replace mRNA exon segments in an in vitro disease model. In this model, a heterozygous insertion of a leucine codon into exon 9 of the plectin gene (PLEC1) leads to aggregation of plectin peptide chains and subsequent protein degradation recapitulating, together with a nonsense mutation on the other allele, the blistering skin disease epidermolysis bullosa simplex with muscular dystrophy (EBS-MD). Transient transfection of EBS-MD fibroblasts with a 5' pre-trans-splicing molecule encoding wild-type exons 2-9 led to specific replacement of the mutated 5' portion of the endogenous PLEC1 transcript through trans-splicing. This treatment reduced the levels of mutant mRNA and restored a wild-type pattern of plectin expression as revealed by immunofluorescence microscopy. When EBS-MD fibroblasts were transfected with retroviral constructs, the level of full-length plectin protein in the corrected fibroblasts increased by 58.7%. Thus, SMaRT may be a promising new tool for treatment of autosomal-dominant genetic diseases.
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PMID:5' trans-splicing repair of the PLEC1 gene. 1826 35

In this issue, Wally et al. (2008) report successful gene expression repair by spliceosome-mediated RNA trans-splicing (SMaRT), a novel achievement in molecular medicine. In their model, SMaRT was able to replace a mutation of the plectin gene in epidermolysis bullosa simplex with muscular dystrophy. This approach is particularly attractive for skin gene therapy of dominant-negative mutations present in a number of blistering genodermatoses.
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PMID:SMaRT technology enables gene expression repair in skin gene therapy. 1798 27

Dysfunction of plectin, a 500-kD cytolinker protein, leads to skin blistering and muscular dystrophy. Using conditional gene targeting in mice, we show that plectin deficiency results in progressive degenerative alterations in striated muscle, including aggregation and partial loss of intermediate filament (IF) networks, detachment of the contractile apparatus from the sarcolemma, profound changes in myofiber costameric cytoarchitecture, and decreased mitochondrial number and function. Analysis of newly generated plectin isoform-specific knockout mouse models revealed that IF aggregates accumulate in distinct cytoplasmic compartments, depending on which isoform is missing. Our data show that two major plectin isoforms expressed in muscle, plectin 1d and 1f, integrate fibers by specifically targeting and linking desmin IFs to Z-disks and costameres, whereas plectin 1b establishes a linkage to mitochondria. Furthermore, disruption of Z-disk and costamere linkages leads to the pathological condition of epidermolysis bullosa with muscular dystrophy. Our findings establish plectin as the major organizer of desmin IFs in myofibers and provide new insights into plectin- and desmin-related muscular dystrophies.
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PMID:Myofiber integrity depends on desmin network targeting to Z-disks and costameres via distinct plectin isoforms. 1849 May 14

Genetic mutations invalidating the genes for integrin alpha6beta4 and, in some cases, plectin are associated with junctional and simplex epidermolysis bullosa with pyloric atresia (PA-JEB and PA-EBS), respectively. These recessive inherited conditions are characterized by pregnancies with fetal bullae, pyloric atresia, polyhydramnios, and neonatal mucocutaneous blistering, which often results in early postnatal demise. To date, first-trimester DNA-based prenatal diagnosis is not applicable to affected kindred carrying as yet unidentified genetic mutations. Here, we show that first-trimester chorionic villi strongly express both integrin alpha6beta4 and plectin, which persist throughout the pregnancy. Based on this observation, we implemented 25 prenatal diagnoses in kindred at risk for PA-EB by immunomapping, which identified three PA-JEB-affected fetuses and 22 healthy ones. In 19 cases, including the three PA-JEB pregnancies that were prematurely terminated, the results were confirmed by chorionic villous DNA-based tests, which also led to the identification of seven previously unreported mutations in the alpha6beta4 integrin genes. Our prediction was further sustained by the birth of 22 healthy babies. These results validate chorionic villi immunofluorescence examination as a tool for prenatal diagnosis of PA-JEB and PA-EBS and indicate that this procedure could be devised for EB with muscular dystrophy, which is also associated with genetic mutations in plectin.
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PMID:Immunofluorescence analysis of villous trophoblasts: a tool for prenatal diagnosis of inherited epidermolysis bullosa with pyloric atresia. 1856 82

Plectin is an important organizer of the keratin filament cytoskeleton in basal keratinocytes. It is essential for anchoring these filaments to the extracellular matrix via hemidesmosomal integrins. Loss of plectin or incorrect function of the protein due to mutations in its gene can lead to various forms of the skin blistering disease, epidermolysis bullosa simplex. Severity and subtype of the disease is dependent on the specific mutation and can be associated with (late-onset) muscular dystrophy or pyloric atresia. Mouse models mimicking the human phenotypes allow detailed study of plectin function.
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PMID:Plectin gene defects lead to various forms of epidermolysis bullosa simplex. 1994 14

We report a rare case of a child with epidermolysis bullosa simplex (EBS) with plectin deficiency but without muscular dystrophy, with severe lesions of the oral cavity, oropharyngeal, hypopharyngeal, laryngeal, tracheal and bronchial mucosa. Case report and a review of the world literature are used. The literature review revealed only five similar patients with EBS without muscular dystrophy complicated by respiratory involvement. This paper highlights the potentially serious complications of the EB in the form of breathing, swallowing and speech difficulties and describes the specific problems encountered in the treatment of this patient. Epidermolysis bullosa (EB) is a group of severe hereditary diseases, primarily of the skin, but which can also involve the respiratory and gastrointestinal tract mucosa. Respiratory tract involvement is usually only found in certain types of EB. The oral cavity and oropharynx are involved more frequently than the hypopharynx, larynx and trachea. Involvement of laryngeal and tracheal mucosa is generally associated with an increased morbidity and mortality, numerous complications and therapeutic difficulties, and is more common in junctional EB and dystrophic EB than in EBS. We present a rare case of a child with EBS and plectin deficiency with pronounced lesions of respiratory tract mucosa from the oral cavity to the bronchi and even extending into the trachea. Deciding on tracheotomy requires thorough consideration and should not be taken lightly.
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PMID:Respiratory tract involvement in a child with epidermolysis bullosa simplex with plectin deficiency: a case report. 2004 46

Plectin is a cytoskeletal linker protein that has a dumbbell-like structure with a long central rod and N- and C-terminal globular domains. Mutations in the gene encoding plectin (PLEC1) cause two distinct autosomal recessive subtypes of epidermolysis bullosa (EB): EB simplex with muscular dystrophy (EBS-MD), and EB simplex with pyloric atresia (EBS-PA). Here, we demonstrate that normal human fibroblasts express two different plectin isoforms including full-length and rodless forms of plectin. We performed detailed analysis of plectin expression patterns in six EBS-MD and three EBS-PA patients. In EBS-PA, expression of all plectin domains was found to be markedly attenuated or completely lost; in EBS-MD, the expression of the N- and C-terminal domains of plectin remained detectable, although the expression of rod domains was absent or markedly reduced. Our data suggest that loss of the full-length plectin isoform with residual expression of the rodless plectin isoform leads to EBS-MD, and that complete loss or marked attenuation of full-length and rodless plectin expression underlies the more severe EBS-PA phenotype. These results also clearly account for the majority of EBS-MD PLEC1 mutation restriction within the large exon 31 that encodes the plectin rod domain, whereas EBS-PA PLEC1 mutations are generally outside exon 31.
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PMID:Plectin expression patterns determine two distinct subtypes of epidermolysis bullosa simplex. 2005 59

Epidermolysis bullosa simplex (EBS) is an inherited skin disorder characterized by separation of the epidermis from the underlying dermis, with the cleavage plane lying within the basal-cell layer of the epithelium. The major clinical subtypes of EBS have a dominant inheritance and have been associated with genetic defects in specific domains of keratins K5 and K14 that result in abnormal organization of the keratin network and cell disruption. Autosomal recessive forms of EBS associated with extracutaneous manifestations, such as muscular dystrophy (MIM 226670) or pyloric atresia (MIM 612138), have been linked to genetic mutations in the gene for plectin (PLEC). PLEC mutations have also been found in 2 families with the rare dominant Ogna form of EBS. This article reviews current knowledge on EBS.
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PMID:Epidermolysis bullosa simplex with muscular dystrophy. 2044 87

Mutations in the PLEC1 gene encoding plectin have been reported in neonatal epidermolysis bullosa simplex with muscular dystrophy of later-onset (EBS-MD). A neuromuscular transmission defect has been reported in one previous patient. We report a boy presenting from birth with features of a congenital muscular dystrophy and late-onset myasthenic symptoms. Repetitive nerve stimulation showed significant decrement, and strength improved with pyridostigmine. Subtle blistering noticed only retrospectively prompted further genetic testing, revealing recessive PLEC1 mutations. We conclude that PLEC1 should be considered in the differential diagnosis of congenital muscular dystrophies and myasthenic syndromes, even in the absence of prominent skin involvement.
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PMID:Congenital muscular dystrophy, myasthenic symptoms and epidermolysis bullosa simplex (EBS) associated with mutations in the PLEC1 gene encoding plectin. 2062 79


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