Rola biopsji mięśnia szkieletowego w diagnostyce chorób nerwowo-mięśniowych

Streszczenie Biopsja mięśnia szkieletowego wykonywana w celach diagnostycznych w chorobach nerwowo-mięśniowych umożliwia ocenę rodzaju procesu chorobowego (pierwotnie mięśniowy czy neurogenny), dostarcza informacji o przebiegu (ostry czy przewlekły) oraz stopniu zaawansowania choroby. W wielu przypadkach zastosowanie dodatkowych technik histochemicznych i immunohistochemicznych pozwala na jednoznaczne rozpoznanie takich schorzeń, jak niektóre dystrofie mięśniowe, glikogenozy, miopatie zapalne oraz miopatie wrodzone. Ocena wycinka mięśniowego w mikroskopie elektronowym umożliwia pewne rozpoznanie dystrofii oczno-gardłowej, miopatii mitochondrialnej i wtrętowego zapalenia mięśni. W niniejszym artykule omówiono objawy kliniczne sugerujące konieczność pobrania wycinka, technikę wykonywania biopsji, zasady wyboru mięśnia do badania, a także praktyczne wskazówki dotyczące przesyłania pobranego wycinka i przygotowania preparatów do oceny w mikroskopie. Przedstawiono ponadto podstawowe zasady dotyczące interpretacji wyniku biopsji mięśnia oraz przydatność kliniczną biopsji mięśnia w dobie zaawansowanej diagnostyki molekularnej

Zmiany histopatologiczne w biopsji mięśnia u 31 chorych z mutacjami w genie kodującym kalpainę 3

Background and purpose At present, more than 20 different forms of limb-girdle muscular dystrophies (LGMDs) are known (at least 7 autosomal dominant and 14 autosomal recessive). Although these different forms show some typical phenotypic characteristics, the existing clinical overlap makes their differential diagnosis difficult. Limb-girdle muscular dystrophy type 2 (LGMD2A) is the most prevalent LGMD in many European as well as Brazilian communities and is caused by mutations in the gene CAPN3. Laboratory testing, such as calpain immunohistochemistry and Western-blot analysis, is not totally reliable, since up to 20% of molecularly confirmed LGMD2A show normal content of calpain 3 and a third of LGMD2A biopsies have normal calpain 3 proteolytic activity in the muscle. Thus, genetic testing is considered as the only reliable diagnostic criterion in LGMD2A. Material and methods In an attempt to find a correlation between genotype and muscle pathology in limb-girdle muscular dystrophy 2A we performed histopathological investigation of a group of 31 patients subdivided according to the type of pathologic CAPN3 gene mutation. Results In all biopsies typical features of muscular dystrophy such as fiber necrosis and regeneration, variation in fiber size and fibrosis were noted. Lobulated fibers were often encountered in the muscle biopsies of LGMD2A patients. Such fibers were more frequent in patients with 550delA mutation. Conclusions These findings may be helpful in establishing diagnostic strategies in LGMD.Wstęp i cel pracy Dotychczas opisano ponad 20 różnych form dystrofii obręczowo-kończynowej (limb girdle muscular dystrophy – LGMD) (co najmniej 7 rodzajów o dziedziczeniu autosomalnym dominującym oraz 14 o dziedziczeniu autosomalnym recesywnym). Pomimo że część z tych chorób można różnicować na podstawie obrazu klinicznego, diagnostykę utrudnia często podobieństwo objawów. Dystrofia obręczowo–kończynowa typu 2A (limb-girdle muscular dystrophy type 2 – LGMD2A), najczęstsza dystrofia mięśniowa w wielu społecznościach (np. w Europie i Brazylii), spowodowana jest przez mutacje w genie kalpainy 3 (CAPN3). Badanie immunohisto-chemiczne kalpainy czy też metodą Western blot nie są wystarczające do ustalenia właściwego rozpoznania (w odpowiednio 1/3 i 20% potwierdzonych genetycznie LGMD2A badania te wypadają prawidłowo). Podstawę rozpoznania tej miopatii stanowi badanie genetyczne. Materiał i metody W pracy przedstawiono wyniki badania zależności między genotypem a analizą histopatologiczną biopsji mięśnia u 31 chorych na LGMD2A. Chorzy podzieleni zostali na grupy według wyników badania genetycznego genu CAPN3 odpowiedzialnego za tę chorobę. Wyniki We wszystkich badanych biopsjach stwierdzano typowe zmiany dystroficzne, takie jak obecność włókien martwiczych i regenerujących, zróżnicowaną wielkość włókien oraz włóknienie. Włókna o nierównomiernym rozkładzie barwień na enzymy oddechowe (lobulated fibers) były często obserwowane w biopsjach chorych z LGMD2A. Tego typu włókna szczególnie często występowały u chorych z mutacją 550delA. Wnioski Wyniki pracy wnoszą nowe informacje ułatwiające diagnostykę LGMD

Phenotype Presentation and Molecular Diagnostic Yield in Non-5q Spinal Muscular Atrophy

BACKGROUND AND OBJECTIVES: Spinal muscular atrophy (SMA) is mainly caused by homozygous SMN1 gene deletions on 5q13. Non-5q SMA patients' series are lacking, and the diagnostic yield of next-generation sequencing (NGS) is largely unknown. The aim of this study was to describe the clinical and genetic landscape of non-5q SMA and evaluate the performance of neuropathy gene panels in these disorders. METHODS: Description of patients with non-5q SMA followed in the different neuromuscular reference centers in France as well as in London, United Kingdom. Patients without a genetic diagnosis had undergone at least a neuropathy or large neuromuscular gene panel. RESULTS: Seventy-one patients from 65 different families were included, mostly sporadic cases (60.6%). At presentation, 21 patients (29.6%) showed exclusive proximal weakness (P-SMA), 35 (49.3%) showed associated distal weakness (PD-SMA), and 15 (21.1%) a scapuloperoneal phenotype (SP-SMA). Thirty-two patients (45.1%) had a genetic diagnosis: BICD2 (n = 9), DYNC1H1 (n = 7), TRPV4 (n = 4), VCP, HSBP1, AR (n = 2), VRK1, DNAJB2, MORC2, ASAH1, HEXB, and unexpectedly, COL6A3 (n = 1). The genetic diagnostic yield was lowest in P-SMA (6/21, 28.6%) compared with PD-SMA (16/35, 45.7%) and SP-SMA (10/15, 66.7%). An earlier disease onset and a family history of the disease or consanguinity were independent predictors of a positive genetic diagnosis. Neuropathy gene panels were performed in 59 patients with a 32.2% diagnostic yield (19/59). In 13 additional patients, a genetic diagnosis was achieved through individual gene sequencing or an alternative neuromuscular NGS. DISCUSSION: Non-5q SMA is genetically heterogeneous, and neuropathy gene panels achieve a molecular diagnosis in one-third of the patients. The diagnostic yield can be increased by sequencing of other neuromuscular and neurometabolic genes. Nevertheless, there is an unmet need to cluster these patients to aid in the identification of new genes

Myasthénie auto-immune séronégative

La myasthénie est une maladie auto-immune avec, dans 80 % des cas, des anticorps dirigés contre le récepteur de l’acétylcholine (anti-RACh) positifs et deux formes cliniques distinctes, oculaire et généralisée. Les formes séronégatives sont relativement rares et cliniquement hétérogènes. Le diagnostic de la myasthénie séronégative reste souvent difficile, notamment pour les formes oculaires et est essentiellement basé sur une symptomatologie fluctuante caractéristique. La découverte des anticorps anti-RACh à faible affinité et des nouveaux anticorps comme les anti-MuSK (dirigés contre le récepteur spécifique de la tyrosine kinase), les anti-LRP4 (dirigés contre la protéine 4 reliée au récepteur des lipoprotéines de faible densité), les anti-agrine ou les anti-cortactine constitue un avancement considérable dans la compréhension de la physiopathologie de la myasthénie. Selon le profil sérologique, il est possible de prévoir la gravité potentielle de la maladie, la réponse aux traitements et le risque de pathologie thymique associée

ASHAM Analyse sociologique des habitudes de vie des adultes atteints de Dystrophie myotonique de type 1 ou maladie de Steinert: Rapport de recherche dans le cadre du premier appel à projets de recherche 2012 Sciences humaines et sociales et maladies rares

Living habits for individuals suffering from a debilitating chronic disease are poorly known, yet essential for effective nursing care to be delivered in the long term. Myotonic dystrophy type 1 (DM1 or Steinert’s disease) is a particular chronic rare disease: it is genetic and progressive; it affects several functions and currently treatment for it is solely symptomatic. Amidst this complexity, it is relatively easy to cater for this clinical diversity in medical terms through multidisciplinary care, but it is more complicated object-side relationship. The objective of this qualitative study was to understand the change in living habits and the social determinants of coping strategies in men and women aged over 20 whose DM1 symptoms have appeared in adulthood. This is research in social sciences and nursing science based on a care issue and an ethno-sociological set of issue. The investigation has shown that patient’s behavior varies according to a set of combined determinants: age, social and professional situation, marital status, values and beliefs, living environment, and so on. Then, there is a large gap between medical representation of disease and day-to-day experience and social life of patients. The stations they passed during their life show various adaptation strategies. That gives us an opportunity to improve their support

Myoadenylate deaminase deficiency: a frequent cause of muscle pain A case detected by exercise testing

International audienc

Investigating glycogenosis type III patients with multi-parametric functional NMR imaging and spectroscopy

Debranching enzyme deficiency (Glycogen storage disease (GSD) type III) causes progressive muscle wasting myopathy. A comprehensive nuclear magnetic resonance study involving spectroscopy (NMRS) and imaging (NMRI) evaluated status and function of calf muscles in 18 GSDIII patients. At rest, (31)P NMRS showed elevated pH and accumulation of anomalous phosphomonoesters, (13)C NMRS quantified excess glycogen accumulation and NMRI demonstrated progressive fat replacement that paralleled muscle weakness. Multi-parametric functional NMR, performed at recovery from a single bout of aerobic exercise, simultaneously assessed oxidative phosphorylation from (31)P NMRS, muscle perfusion and BOLD, a marker of blood oxygenation, from arterial spin labeled NMRI, and oxygen uptake from deoxymyoglobin proton NMRS. While blocked glycogenolysis caused inadequate substrate supply to the mitochondria, combined measurements suggested that altered perfusion was also responsible for impaired post-exercise phosphocreatine recovery and could contribute to exercise intolerance in GSDIII. These non-invasive investigations provide new indices to quantify the progression of GSDIII.status: publishe

Muscle imaging in patients with tubular aggregate myopathy caused by mutations in STIM1

Tubular aggregate myopathy is a genetically heterogeneous disease characterized by tubular aggregates as the hallmark on muscle biopsy. Mutations in STIM1 have recently been identified as one genetic cause in a number of tubular aggregate myopathy cases. To characterize the pattern of muscle involvement in this disease, upper and lower girdles and lower limbs were imaged in five patients with mutations in STIM1, and the scans were compared with two patients with tubular aggregate myopathy not caused by mutations in STIM1. A common pattern of involvement was found in STIM1-mutated patients, although with variable extent and severity of lesions. In the upper girdle, the subscapularis muscle was invariably affected. In the lower limbs, all the patients showed a consistent involvement of the flexor hallucis longus, which is very rarely affected in other muscle diseases, and a diffuse involvement of thigh and posterior leg with sparing of gracilis, tibialis anterior and, to a lesser extent, short head of biceps femoris. Mutations in STIM1 are associated with a homogeneous involvement on imaging despite variable clinical features. Muscle imaging can be useful in identifying STIM1-mutated patients especially among other forms of tubular aggregate myopathy