BACKGROUND AND PURPOSE: Centronuclear myopathy (CNM) is characterized by the presence of central nuclei within a large number of muscle fibers. Mutations of the dynamin 2 gene (DNM2) are common causes of autosomal dominant or sporadic CNM. The aim of this study was to characterize the clinical and pathological features of CNM relative to the presence of DNM2 mutations. METHODS: Six patients with clinical and pathological features of CNM were recruited. Detailed clinical and pathological findings were analyzed according to the presence of DNM2 mutations. RESULTS: We detected DNM2 mutations in four of the six sporadic CNM patients, and identified the following distinct clinical and pathological features in those patients with DNM2 mutations: preferential involvement of the distal lower limbs, typical nuclear centralization, and radially distributed sarcoplasmic strands in muscle pathology. In contrast, those without DNM2 mutations exhibited rather diffuse muscular involvement, and nuclear internalization and myofibrillar disorganization were more pronounced features of their muscle pathology. CONCLUSIONS: These findings suggest the presence of specific features in Korean CNM patients. A detailed clinical and pathological examination of CNM patients would be helpful for molecular genetic analyses of this condition.
Dynamin II ; Humans ; Lower Extremity ; Molecular Biology ; Muscles ; Myopathies, Structural, Congenital* ; Pathology

Non-progressive congenital myopathy is a group of muscle diseases occurring at birth or during teenage years. A number of new reports of congenital myopathy, such as homogeneous bodies myopathy, muscle quality control myopathy and type 1 fiber predominance have recently been reported, but they lack of sufficient quantity and constant clinico-pathologic manifestations. This paper reports two cases of congenital myopathy with type 1 fiber predominance confirmed by muscle biopsy. The clinical manifestations of the two children (a 4.5-year-old girl and an 11-year-old boy) included non-progressive symptoms of muscle weakness, skeletal deformities and other clinical features of congenital myopathy. The physical examinations showed a long face or figure and funnel chest or kyphosis/scoliosis, high palatal arch and wing-like shoulder. Serum levels of creatine kinase were normal but slightly elevated serum lactate dehydrogenase levels were noted in the two children. The skeletal muscle biopsy by ATPase staining showed that type 1 fibers accounted for more than 90% of the total number of muscle fibers. No other abnormal pathological changes, such as central cores, muscle tube and central nuclei, were found in the two children.
Diagnosis, Differential ; Female ; Humans ; Infant ; Male ; Muscle, Skeletal ; pathology ; Myopathies, Structural, Congenital ; diagnosis ; pathology ; therapy

X-linked myotubular myopathy (XLMTM) is a rare congenital muscle disorder, caused by mutations in the MTM1 gene. Affected male infants present severe hypotonia, and generalized muscle weakness, and the disorder is most often complicated by respiratory failure. Herein, we describe a family with 2 infants with XLMTM which was diagnosed by gene analysis and muscle biopsy. In both cases, histological findings of muscle showed severely hypoplastic muscle fibers with centrally placed nuclei. From the family gene analysis, the Arg486STOP mutation in the MTM1 gene was confirmed.
*Codon, Nonsense ; Humans ; Male ; Muscle Hypotonia/genetics/pathology ; Myopathies, Structural, Congenital/*genetics/pathology ; Pedigree ; Protein Tyrosine Phosphatases, Non-Receptor/*genetics

OBJECTIVETo analyze the clinical and pathological features of the centronuclear myopathy (CNM) in 5 Chinese patients and evaluate their diagnostic and differential diagnostic value.

METHODSA standard series of histochemical and enzymohistochemical investigations were performed on all muscle specimens of CNM cases obtained via biopsy. The clinical manifestations and myopathological features of 5 CNM patients were retrospectively analyzed.

RESULTSThe age of onset ranged from 3 to 12 years. All patients primarily presented with limb girdle muscle weakness. In 3 patients extraocular muscles, facial muscles and cervical muscles were affected, respectively. The proximal muscles were affected more seriously than the distal and the lower limbs more seriously than the upper. Tendon reflex was reduced and no evident muscular atrophy was seen. The course of the disease ranged from 4 to 46 years and progressed slowly. The ability of walking could be maintained for many years and the fast movements such as running and jumping were impaired early. The serum creatine kinase (CK) level was normal or elevated slightly. Electromyography showed myopathic pattern in all cases. Two patients (mother and son) were from the same family and the son's two siblings had similar symptoms indicating autosomal dominant inherited pattern. There was mild variation in fiber size and most small fibers were round. Interstitial tissue increase slightly. Fibers with centrally placed nuclei accounted for 23% - 93%. Neither necrotic and regenerated fibers nor infiltration of inflammatory cells were seen. Type I fiber predominance and hypotrophy were present in all patients. Abnormal arrangement of the sarcoplasmic strands in appearance of "spokes of a wheel", increased oxidative enzyme activity around centronuclear and perinuclear halo were observed in 2 patients by NADH-TR staining.

CONCLUSIONSFor the patients who had the onset during the childhood and presented with slow progressive limb girdle muscle weakness, disability of fast movements and normal serum CK level, the possibility of benign congenital myopathy should be considered. High percentage of centronuclear fibers as well as type I fiber predominance and hypotrophy in muscle biopsy pathology may provide a morphological evidence for the definite diagnosis of CNM.

Adolescent ; Adult ; Biopsy ; Child ; Child, Preschool ; Creatine Kinase ; blood ; Female ; Humans ; Male ; Middle Aged ; Myopathies, Structural, Congenital ; diagnosis ; pathology ; Retrospective Studies

Centronuclear myopathies are clinically and genetically heterogenous diseases with common histological findings, namely, centrally located nuclei in muscle fibers with a predominance and hypotrophy of type 1 fibers. We describe two cases from one family with autosomal dominant centronuclear myopathy with unusual clinical features that had initially suggested distal myopathy. Clinically, the patients presented with muscle weakness and atrophy localized mainly to the posterior compartment of the distal lower extremities. Magnetic resonance imaging revealed predominant atrophy and fatty changes of bilateral gastrocnemius and soleus muscles. This report demonstrates the expanding clinical heterogeneity of autosomal dominant centronuclear myopathy.
Adolescent ; Female ; *Genes, Dominant ; Humans ; Middle Aged ; Muscle, Skeletal/pathology ; Myopathies, Structural, Congenital/*genetics/*pathology

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.
Myopathies, Structural, Congenital/*diagnosis ; Muscular Diseases/*pathology ; Muscles/pathology ; Male ; Infant ; Humans ; Female ; Child, Preschool ; Child ; Biopsy ; Adult

Centronuclear myopathy is a rare congenital myopathy, which is characterized by centrally located nuclei and hypotrophy or predominance of type 1 fibers in muscle pathology. It is classified into three forms according to the clinical features and inheritance pattern: the X-linked recessive, the autosomal recessive, and the autosomal dominant forms. We report a case of a patient with generalized muscle weakness, poor muscle bulk, and dysmorphic features who was diagnosed as centronuclear myopathy.
Humans ; Inheritance Patterns ; Muscle Weakness ; Muscular Diseases ; Myopathies, Structural, Congenital* ; Pathology

Child ; Humans ; Male ; Muscles ; pathology ; physiopathology ; Myopathies, Structural, Congenital ; diagnosis ; Prognosis

Centronuclear myopathy (CNM) is a rare congenital myopathy that is characterized by centrally placed nuclei in the muscle fibers. Based on the time of onset and the mode of inheritance, CNM can be divided into three distinct forms: the severe neonatal form, the childhood onset form, and the adult onset form. This paper describes the case of a female patient with CNM, in whom the disease manifested itself in the fifth decade of life, without any prior family history of such disorders. To the best of our knowledge, this is a rare case of late adult-onset CNM.
Age of Onset ; Female ; Human ; Middle Aged ; Myopathies, Structural, Congenital/genetics/*pathology ; Pedigree

Congenital fiber type disproportion (CFTD) is a form of congenital myopathy characterized by histologic findings of the smallness of type 1 fiber and type 1 fiber predominance. It is usually associated with hypotonia and motor weakness of the limb muscles at birth or the neonatal period. We report a 6-year-old girl with limb weakness and ophthalmoplegia, whose muscle pathology showed the classic pattern of CFTD without any other abnormality.
Child ; Extremities ; Female ; Humans ; Muscle Hypotonia ; Muscles ; Muscular Diseases ; Myopathies, Structural, Congenital* ; Ophthalmoplegia* ; Parturition ; Pathology