Search results for " myopathy"
showing 10 items of 69 documents
Mitochondrial myopathy--a result of clofibrate/etofibrate treatment? Case report.
1985
A 66-year-old man had developed a myopathy while undergoing several periods of etofibrate and clofibrate therapy over the past 5 years. Discontinuation of etofibrate treatment failed to reverse his muscle illness which, however, did not progress. A muscle biopsy revealed a chronic myopathy marked by abundant, abnormally structured muscle mitochondria. His mitochondrial myopathy may represent a forme fruste of the Kearns-Sayre syndrome or other types of mitochondrial myopathy, clinically made evident by the etofibrate/clofibrate therapy, or a permanent, adverse side effect of clofibrate treatment. If the latter assumption proves to be correct, it will indicate that clofibrate therapy may ind…
Mutations of mitochondrial DNA and human death.
1990
In the skeletal muscle of patients with mitochondrial myopathies (Kearns-Sayre syndrome and chronic progressive external ophthalmoplegia) and in the heart and skeletal muscle of healthy persons cells lacking cytochrome c oxidase are found. The respiratory-defective cells have the following features in common: onset of the defect at juvenile or adult age; progressive character of the defect with increasing age; and focal pattern of respiratory-deficient cells (fibers). A statistic mutation of mtDNA in affected cells is suggested to cause the defect of mitochondrial function. It is postulated that the continuous accumulation of respiratory-deficient cells, mainly in the human heart with incre…
Familial mixed congenital myopathy with rigid spine phenotype
1997
We describe a father and daughter with a rigid spine syndrome and proximal myopathy. The index patient was a 42-year-old man, who died from respiratory failure after a lifelong, slowly progressive proximal myopathy and a rigid spine phenotype. This was morphologically characterized by cytoplasmic bodies, increased desmin, features of reducing-body myopathy, and sarcoplasmic and intranuclear tubulofilamentous inclusions. These cases are characterized by an early onset and possibly autosomal-dominant inheritance, with associated complex structural hallmarks of both desmin-related and inclusion body myopathies. Together they may be defined as a complex mixed congenital myopathy with a rigid sp…
Proteomic identification of FHL1 as the protein mutated in human reducing body myopathy
2007
Reducing body myopathy (RBM) is a rare disorder causing progressive muscular weakness characterized by aggresome-like inclusions in the myofibrils. Identification of genes responsible for RBM by traditional genetic approaches has been impossible due to the frequently sporadic occurrence in affected patients and small family sizes. As an alternative approach to gene identification, we used laser microdissection of intracytoplasmic inclusions identified in patient muscle biopsies, followed by nanoflow liquid chromatography-tandem mass spectrometry and proteomic analysis. The most prominent component of the inclusions was the Xq26.3-encoded four and a half LIM domain 1 (FHL1) protein, expresse…
Congenital myopathies at their molecular dawning
2003
The introduction and application of molecular techniques have commenced to influence and alter the nosology of congenital myopathies. Long-known entities such as nemaline myopathies, core diseases, and desmin-related myopathies have now been found to be caused by unequivocal mutations. Several of these mutations and their genes have been identified by analyzing aggregates of proteins within muscle fibers as a morphological hallmark as in desminopathy and actinopathy, the latter a subtype among the nemaline myopathies. Immunohistochemistry has played a crucial role in recognizing this new group of protein aggregate myopathies within the spectrum of congenital myopathies. It is to be expected…
Congenital Myopathies in the New Millennium
2005
Few medical disciplines have benefited so enormously from the molecular revolution as myology. Whereas the congenital myopathies have flourished from enzyme histochemistry and electron microscopy, defining individual congenital myopathies by structural abnormalities, genetic research has only recently focused on congenital myopathies. However, a number of congenital myopathies have been molecularly elucidated: central and multiminicore diseases, nemaline myopathy, myotubular myopathy, and congenital myopathy marked by aggregation of proteins, giving rise to the concept of protein aggregate myopathies, to which now desminopathies, α-B crystallinopathies, selenoproteinopathy, myotilinopathy,…
Protein Aggregation in Muscle Fibers and Respective Neuromuscular Disorders
2007
Protein aggregation in muscle fibers may be a nonspecific phenomenon such as occurring in cores or ragged red fibers. However, it may also be a disease-specific and disease-significant phenomenon constituting protein aggregate myopathies (PAMs). These may be divided into two classes: The first one is marked by impaired extralysosomal degradation of proteins, catabolic PAM, encompassing desmin-related myopathies. Mutant proteins, that is, desmin, myotilin, or α-B crystallin, defy protein degradation, aggregate and associate with other proteins within muscle fibers, hence marking desminopathies, myotilinopathies, and α-B crystallinopathies. A second class of PAM encompasses those apparently a…
Nuclear actin aggregation is a hallmark of anti-synthetase syndrome-induced dysimmune myopathy
2015
Objective: To analyze antisynthetase syndrome–associated myositis by modern myopathologic methods and to define its place in the spectrum of idiopathic inflammatory myopathies (IIMs). Methods: Skeletal muscle biopsies from antisynthetase syndrome–associated myositis and other IIMs from different institutions worldwide were analyzed by histopathology, quantitative PCR, and electron microscopy. Results: Myonuclear actin filament inclusions were identified as a unique morphologic hallmark of antisynthetase syndrome–associated myositis. Nuclear actin inclusions were never found in dermatomyositis, polymyositis, sporadic inclusion body myositis, autoimmune necrotizing myopathy associated with si…
Cap disease uncapped
2007
With the advent of enzyme histochemistry and electron microscopy, the new nosographic group of congenital myopathies hailed as ‘‘new myopathies’’ [1] was established, largely based on morphological features in biopsied muscle specimens although clinically early (congenital) onset and mild progression were also attributed to these childhood myopathies. When molecular investigations of patients with hereditary neuromuscular diseases began, earlier classifications based on clinical, morphological, and metabolic criteria started to quake, most conspicuously observed in the group of limb girdle muscular dystrophy or limb girdle muscular syndrome, which now comprise seven autosomal dominant (LGMD…
Neonatal form of nemaline myopathy, muscle immaturity, and a microvascular injury.
1990
An infant with a neonatal form of nemaline myopathy showed ultrastructural features of muscle immaturity. Immaturity was characterized by an abnormal presence of myotubes, as well as cells in clusters within a common basement membrane and a great number of satellite cells adhering to very small muscle fibers. In addition, degenerative changes and a severe microvascular lesion were observed. The pathologic findings in the muscle of this patient were those of neonatal nemaline myopathy complicating severe microvascular injury, possibly induced by an unknown toxic agent. ( J Child Neurol 1990;5:122-126).