1
|
Rathore G, Kang PB. Pediatric Neuromuscular Diseases. Pediatr Neurol 2023; 149:1-14. [PMID: 37757659 DOI: 10.1016/j.pediatrneurol.2023.08.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 07/25/2023] [Accepted: 08/24/2023] [Indexed: 09/29/2023]
Abstract
The diagnostic and referral workflow for children with neuromuscular disorders is evolving, particularly as newborn screening programs are expanding in tandem with novel therapeutic developments. However, for the children who present with symptoms and signs of potential neuromuscular disorders, anatomic localization, guided initially by careful history and physical examination, continues to be the cardinal initial step in the diagnostic evaluation. It is important to consider whether the localization is more likely to be in the lower motor neuron, peripheral nerve, neuromuscular junction, or muscle. After that, disease etiologies can be divided broadly into inherited versus acquired categories. Considerations of localization and etiologies will help generate a differential diagnosis, which in turn will guide diagnostic testing. Once a diagnosis is made, it is important to be aware of current treatment options, as a number of new therapies for some of these disorders have been approved in recent years. Families are also increasingly interested in clinical research, which may include natural history studies and interventional clinical trials. Such research has proliferated for rare neuromuscular diseases, leading to exciting advances in diagnostic and therapeutic technologies, promising dramatic changes in the landscape of these disorders in the years to come.
Collapse
Affiliation(s)
- Geetanjali Rathore
- Division of Neurology, Department of Pediatrics, University of Nebraska College of Medicine, Omaha, Nebraska
| | - Peter B Kang
- Paul and Sheila Wellstone Muscular Dystrophy Center and Department of Neurology, University of Minnesota Medical School, Minneapolis, Minnesota; Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota.
| |
Collapse
|
2
|
Malfatti E, Lehtokari VL, Böhm J, De Winter JM, Schäffer U, Estournet B, Quijano-Roy S, Monges S, Lubieniecki F, Bellance R, Viou MT, Madelaine A, Wu B, Taratuto AL, Eymard B, Pelin K, Fardeau M, Ottenheijm CAC, Wallgren-Pettersson C, Laporte J, Romero NB. Muscle histopathology in nebulin-related nemaline myopathy: ultrastrastructural findings correlated to disease severity and genotype. Acta Neuropathol Commun 2014; 2:44. [PMID: 24725366 PMCID: PMC4234932 DOI: 10.1186/2051-5960-2-44] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 03/20/2014] [Indexed: 01/09/2023] Open
Abstract
Nemaline myopathy (NM) is a rare congenital myopathy characterised by hypotonia, muscle weakness, and often skeletal muscle deformities with the presence of nemaline bodies (rods) in the muscle biopsy. The nebulin (NEB) gene is the most commonly mutated and is thought to account for approximately 50% of genetically diagnosed cases of NM. We undertook a detailed muscle morphological analysis of 14 NEB-mutated NM patients with different clinical forms to define muscle pathological patterns and correlate them with clinical course and genotype. Three groups were identified according to clinical severity. Group 1 (n = 5) comprises severe/lethal NM and biopsy in the first days of life. Group 2 (n = 4) includes intermediate NM and biopsy in infancy. Group 3 (n = 5) comprises typical/mild NM and biopsy in childhood or early adult life. Biopsies underwent histoenzymological, immunohistochemical and ultrastructural analysis. Fibre type distribution patterns, rod characteristics, distribution and localization were investigated. Contractile performance was studied in muscle fibre preparations isolated from seven muscle biopsies from each of the three groups. G1 showed significant myofibrillar dissociation and smallness with scattered globular rods in one third of fibres; there was no type 1 predominance. G2 presented milder sarcomeric dissociation, dispersed or clustered nemaline bodies, and type 1 predominance/uniformity. In contrast, G3 had well-delimited clusters of subsarcolemmal elongated rods and type 1 uniformity without sarcomeric alterations. In accordance with the clinical and morphological data, functional studies revealed markedly low forces in muscle bundles from G1 and a better contractile performance in muscle bundles from biopsies of patients from G2, and G3. In conclusion NEB-mutated NM patients present a wide spectrum of morphological features. It is difficult to establish firm genotype phenotype correlation. Interestingly, there was a correlation between clinical severity on the one hand and the degree of sarcomeric dissociation and contractility efficiency on the other. By contrast the percentage of fibres occupied by rods, as well as the quantity and the sub sarcolemmal position of rods, appears to inversely correlate with severity. Based on our observations, we propose myofibrillar dissociation and changes in contractility as an important cause of muscle weakness in NEB-mutated NM patients.
Collapse
|
3
|
Sharma MC, Jain D, Sarkar C, Goebel HH. Congenital myopathies--a comprehensive update of recent advancements. Acta Neurol Scand 2009; 119:281-92. [PMID: 19133863 DOI: 10.1111/j.1600-0404.2008.01126.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The congenital myopathies are relatively newly discovered compared with other categories of muscle diseases. Current research continues to clarify and classify the congenital myopathies. These pose a diagnostic problem and cannot be diagnosed by routine hematoxylin and eosin stain. A lot of special techniques are required to diagnose them correctly and it's various subtypes. The disease specific structural changes seen in the muscle are detected by enzyme histochemistry, immunohistochemistry and electron microscopy. Through this review we provide an up-to-date analysis of congenital myopathies including clinical and pathologic aspects.
Collapse
Affiliation(s)
- M C Sharma
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India.
| | | | | | | |
Collapse
|
4
|
Abstract
PURPOSE OF REVIEW The aim of this review is to provide an up-to-date personal analysis of current congenital myopathy research. RECENT FINDINGS In the past year novel congenital myopathies have been suggested, genes have been discovered for some of the congenital myopathies for the first time (beta-tropomyosin in cap disease and perhaps skeletal muscle alpha-actin in Zebra body myopathy), further genes have been identified for congenital myopathies where other genes had already been found (cofilin in nemaline myopathy, selenoprotein N in congenital fibre type disproportion) and recessive myosin storage myopathy was associated with homozygous mutation of slow-skeletal/beta-cardiac myosin which was already known to be mutated in dominant myosin storage myopathy. There has been further clarification of the pathobiology of the congenital myopathies, including determination of the basis of epigenetic effects: silencing of the normal allele in recessive central core disease and persistence of cardiac (fetal) alpha-actin in nemaline myopathy patients with no skeletal actin. SUMMARY The increased understanding of the genes and pathobiology of the congenital myopathies that is developing should ultimately lead to effective treatments.
Collapse
Affiliation(s)
- Nigel G Laing
- Centre for Medical Research, University of Western Australia and Western Australian Institute for Medical Research, Nedlands, Western Australia, Australia.
| |
Collapse
|
5
|
Na SJ, Kim WK, Kim TS, Kang SW, Lee EY, Choi YC. Comparison of clinical characteristics between congenital fiber type disproportion myopathy and congenital myopathy with type 1 fiber predominance. Yonsei Med J 2006; 47:513-8. [PMID: 16941741 PMCID: PMC2687732 DOI: 10.3349/ymj.2006.47.4.513] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Congenital myopathies are clinical and genetic heterogeneous disorders characterized by skeletal muscle weakness and specific structural changes in muscle fiber. Congenital myopathy with fiber type disproportion (CFTD) is an established disorder of congenital myopathy. CFTD is characterized by non-progressive childhood neuromuscular disorders with a relatively good prognosis and type 1 fiber predominance and smallness. Congenital myopathy with type 1 fiber predominance (CMT1P) is also a distinct entity of congenital myopathy characterized by non-progressive childhood neuromuscular disorders and type 1 fiber predominance without smallness. Little is known about CMT1P. Clinical characteristics, including dysmorphic features such as hip dislocation, kyphoscoliosis, contracture, and high arch palate, were analyzed along with laboratory and muscle pathologies in six patients with CMT1P and three patients with CFTD. The clinical manifestations of CFTD and CMT1P were similar. However, the frequency of dysmorphic features is less in CMT1P than in CFTD. Long term observational studies of CMT1P are needed to determine if it will change to another form of congenital myopathy or if CMT1P is a distinct clinical entity.
Collapse
Affiliation(s)
- Sang-Jun Na
- Department of Neurology, Konyang University College of Medicine, Daejeon, Korea
| | - Woo-Kyung Kim
- Department of Neurology, Hallym University College of Medicine, Seoul, Korea
| | - Tai-Seung Kim
- Department of Pathology, Brain Korea 21 Project for Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Seong-Woong Kang
- Department of Rehabilitation Medicine, Brain Korea 21 Project for Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Eun-Young Lee
- Department of Neurology, Brain Korea 21 Project for Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Young-Chul Choi
- Department of Neurology, Brain Korea 21 Project for Medicine, Yonsei University College of Medicine, Seoul, Korea
| |
Collapse
|
6
|
Abstract
The congenital myopathies and congenital muscular dystrophies are a group of relatively infrequent neuromuscular disorders. Ultimate understanding of these disorders, however, will undoubtedly shed considerable light on skeletal muscle development and function. Three classical congenital myopathies are central core disease, nemaline myopathy, and centronuclear myopathy. The congenital muscular dystrophies are often distinguished by whether or not they are associated with clinically evident cerebral involvement.
Collapse
Affiliation(s)
- Jack E Riggs
- Department of Neurology, West Virginia University School of Medicine, Health Sciences Center, One Medical Center Drive, Room G-103, Box 9180, Morgantown, WV 26506-9180, USA.
| | | | | |
Collapse
|
7
|
Abstract
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 that other congenital myopathies marked by inclusion bodies may turn out to be such protein aggregate myopathies, depending on analysis of individual proteins within these protein aggregates and their association with putative gene mutations.
Collapse
Affiliation(s)
- Hans H Goebel
- Department of Neuropathology, Johannes Gutenberg University, Medical Center, Langenbeckstrasse 1, 55131 Mainz, Germany.
| |
Collapse
|
8
|
Mrak RE. The Big Eye in the 21st century: the role of electron microscopy in modern diagnostic neuropathology. J Neuropathol Exp Neurol 2002; 61:1027-39. [PMID: 12484565 DOI: 10.1093/jnen/61.12.1027] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Electron microscopy (EM) remains a powerful and even essential tool in modern diagnostic neuropathology. tumors are still encountered that defy histological or immunohistochemical classification, and EM can often provide answers in these cases. Tumors of the CNS for which EM is useful include unusual or atypical variants of meningioma, ependymoma, and schwannoma; oligodendroglioma-like tumors composed of small "clear" cells; and small "blue cell" tumors of childhood. EM is of great value in identifying site of origin for metastatic adenocarcinomas of unknown origin-an under-recognized and under-utilized potential for this technique. EM is useful in the diagnosis of peripheral nerve sheath tumors and gastrointestinal autonomic nerve tumors. EM is also important in the evaluation of certain congenital, inherited and metabolic diseases-including ceroid lipofuscinoses, CADASIL syndrome, certain myopathies, and mitochondrial encephalomyopathies--and of certain toxic and drug-induced peripheral neuropathies. An important application of EM is its utility in initiating a workup of an atypical tumor or metabolic condition, for which clinical and histological clues point in no obvious direction. In these situations, EM may provide either an answer outright (including answers to questions not asked) or important clues that guide further workup and narrow the range of diagnostic possibilities.
Collapse
Affiliation(s)
- Robert E Mrak
- Department of Pathology, University of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, AR 72205, USA
| |
Collapse
|
9
|
Abstract
The protein surplus myopathies have emerged as a newly recognized subgroup of morphologically defined myopathies within the spectrum of congenital myopathies because of the accumulation of protein aggregates, some of them mutant proteins. Currently, nosologic, including molecular criteria include desmin-related myopathies, actinopathies, and hereditary inclusion body myopathies, whereas hyaline body myopathy is still a putative form of protein surplus myopathy because of lack of any molecular data. The congenital myopathies (CM), foremost including nemaline and myotubular myopathies, have given evidence that, despite their epidemiologic rarity, the molecular age has dawned in CM and has even revealed surprising new nosologic features requiring reassessment and reclassification of certain CM. It is to be expected that a recently updated ENMC Consortium on "Protein surplus and other congenital myopathies" may procure important new information.
Collapse
Affiliation(s)
- Hans H Goebel
- Department of Neuropathology, Johannes Gutenberg University Medical Center, Mainz, Germany
| | | |
Collapse
|
10
|
Flanigan KM, Kerr L, Bromberg MB, Leonard C, Tsuruda J, Zhang P, Gonzalez-Gomez I, Cohn R, Campbell KP, Leppert M. Congenital muscular dystrophy with rigid spine syndrome: A clinical, pathological, radiological, and genetic study. Ann Neurol 2001. [DOI: 10.1002/1531-8249(200002)47:2<152::aid-ana4>3.0.co;2-u] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|