No abstract
Inflammatory myopathies comprise a multitude of diverse diseases, most often occurring in complex clinical settings. To ensure accurate diagnosis, multidisciplinary expertise is required. Here, we propose a comprehensive myositis classification that incorporates clinical, morphological and molecular data as well as autoantibody profile. This review focuses on recent advances in myositis research, in particular, the correlation between autoantibodies and morphological or clinical phenotypes that can be used as the basis for an 'integrated' classification system.
Immune-mediated necrotizing myopathies (IMNMs) are now well recognized among the so-called idiopathic inflammatory myopathies (IIMs), which also comprise dermatomyositis (DM), polymyositis (PM), sporadic inclusion body myositis (sIBM) and non-specific myositis. All of these conditions are defined on the basis of distinct clinical symptoms, in combination with results derived from muscle biopsy and additional data, such as measurement of the serum creatine kinase (CK) level as well as myositis-associated and myositis-specific autoantibodies, electromyography (EMG) and modern imaging techniques. Importantly, diagnosis of one of the above mentioned myositis forms implies a specific clinical syndrome or a distinct disease. However, there is considerable clinical heterogeneity, and overlap requiring further diagnostic precision. Classification and subclassification of IIMs are highly debated and the subjects of intense research, especially as clinical trials with anti-inflammatory agents should follow universally defined and accepted criteria. This review focuses on the description of the spectrum of immune-mediated necrotizing myopathies with an emphasis on their myopathological features.
As a consequence of C terminal FHL1 gene mutations, the X-linked myopathy characterized by postural muscle atrophy (XMPMA) phenotype and morphotype with cytoplasmic bodies are found. In the spectrum of FHL1opathies, the preserved FHL1C protein is likely responsible for the moderate XMPMA phenotype compared with the more severe reducing body myopathy/scapuloperoneal myopathy phenotype.
We report six patients with Emery-Dreifuss muscular dystrophy (EDMD) and four patients including one female with EDMD phenotype (EDMDP). This series includes one sporadic case who had previously been reported in this journal under the diagnosis of "rigid spine syndrome" in 1977. Time of observation ranged from three to ten years. Detailed cardiological assessment was performed in all patients, skeletal muscle biopsies were obtained from 9 out of 10 and cardiac muscle biopsies from 2 out of 10 patients. One patient showed evidence of cardiomyopathy in the absence of clinically apparent neuromuscular disease and one sibling of another EDMD patient reportedly had a similar combination of symptoms which, to our knowledge, has not yet been reported. Cardiac involvement was found to consist of four independent, albeit often combined features: 1) impairment of impulse generating cells; 2) conduction defects with atrial preponderance; 3) increased atrial and ventricular heterotopia; and 4) functional impairment of ventricular myocardium. Ventricular involvement as apparent from ventricular heterotopia, abnormal enddiastolic diameter, decrease of contractility and/or morphological evidence of ventricular myocardial disease was found in 7 out of 10 patients and confirmed by myocardial histopathology in two EDMD patients. In one myocardial biopsy extensive accumulations of intermediate filaments were observed, a rare finding, which has not been linked to EDMD before. Skeletal muscle biopsies showed evidence of myopathy throughout but several equivocal features such as fibre type grouping in EDMD and fibre type disproportion in EDMDP were also observed. The variability of clinical manifestation of both cardiac and neuromuscular disease encompassed a broader spectrum than apparent from the literature. The consequences for the inherent differential diagnosis are discussed.
Three cases of symptomatic neuralgia of the trigeminal nerve due to an amyloidoma in the gasserian ganglion are described. The correct diagnosis was not made prior to histological examination of the surgical biopsy specimens. Medical history and clinical observation led to the diagnosis of a malignant process of the nasal cavities in the first patient; of an inflammatory dental focus in the second patient; and of multiple sclerosis in the third patient. CT findings were normal in cases 1 and 2; in case 3, a schwannoma was suspected from the CT appearances. In case 1, MRI had not been performed; in cases 2 and 3, MRI revealed a tumour mass which was also considered to be a schwannoma. Histologically, the tumours consisted of masses of amyloid deposits which had largely replaced the pre-existing ganglionic cells and satellite cells. Electron microscopy confirmed the fibrillar structure of the deposits. Immunohistochemistry and immunocytochemistry revealed the amyloid to belong to the AL-lambda subtype.
We report a novel LIM2 domain mutation in FHL1 in a previously reported family with RBM with cytoplasmic bodies and spinal rigidity. While the male index patient was significantly affected, female carriers show varying manifestations and may be asymptomatic, likely reflecting varying degrees of X-inactivation. RBM continues to be associated with mutations in the LIM2 domain of FHL1. We also confirm our earlier observation that mutations at the N-terminal end of the LIM2 domain seem to be milder compared to mutations seen at the C-terminal part of the domain which cause severe disease even in female carriers.
Dystrophin is the gene product of the Duchenne (DMD) and Becker (BMD) muscular dystrophy gene locus on the short arm of the X chromosome. Complete lack of dystrophin is pathognomonic for DMD and variable changes of the molecule may be observed in the milder allelic form of BMD. In the present study the two methods available for dystrophin assessment, immunofluorescence detections on cryosections (IF) and Western blotting (WB) were systematically compared using polyclonal and monoclonal antibodies to various regions along the dystrophin molecule. A total of 95 patients with DMD or BMD were investigated including two female patients. Dystrophin assessment revealed abnormal abundance and/or distribution in all 95 patients with DMD or BMD. Only trace amounts of dystrophin were detected in 29% of the DMD patients and complete lack of dystrophin was found in 71%. In two females with DMD but with normal karyotype single dystrophin-positive fibres were found among more than 90% negative fibres. Out of 26 patients with BMD 19 (73%) had a dystrophin molecule of abnormal molecular weight. The results of IF were largely compatible with those from WB but differences were also observed, e.g. one barely symptomatic BMD patient with dystrophin of increased molecular weight showed normal IF. Out of four carriers of BMD three showed evidence of reduced dystrophin immunostaining in some muscle fibres. In 20 other patients limb girdle muscualar dystrophy with "Duchenne-like" or "Becker-like" phenotype was suspected because dystrophin showed normal abundance and distribution. Focal discontinuity of muscle cell-surface dystrophin staining was observed in one patient with a congenital, autosomal recessive muscular dystrophy and in one out of five patients with polymyositis/dermatomyositis. The study emphasizes the need for, and value of, dystrophin assessment in every case of suspected BMD or DMD.
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