OBJECTIVES: To study clinical manifestations and gene mutation features of neonates with centronuclear myopathy. METHODS: A retrospective analysis was conducted on the medical data of 5 neonates with centronuclear myopathy diagnosed in the Neonatal Intensive Care Unit of Children's Hospital, Zhejiang University School of Medicine from January 2020 to August 2024. The data included gender, gestational age, birth weight, Apgar score, clinical manifestations, creatine kinase level, electromyography, genetic testing results and the outcomes of the infants. RESULTS: All 5 male neonates had a history of postpartum asphyxia and resuscitation. They all presented with hypotonia, myasthenia, and respiratory failure; two neonates also had swallowing dysfunction. Of the five neonates, three had normal creatine kinase levels, while two had slightly elevated levels. Electromyography was performed for three neonates, among whom two had myogenic damage. MTM1 gene mutations were identified by genetic testing in all five neonates, including two nonsense mutations and three missense mutations, among which one variant had not been previously reported. Four mutations were inherited from the mother, and the other one was a de novo mutation. The five neonates showed no clinical improvement following treatment, failed weaning from mechanical ventilation, and ultimately died after withdrawal of life-sustaining therapy. CONCLUSIONS Centronuclear myopathy caused by MTM1 gene mutation often has a severe phenotype and a poor prognosis, and it should be considered for neonates with hypotonia and myasthenia after birth. Genetic testing should be performed as soon as possible.
Humans ; Myopathies, Structural, Congenital/genetics* ; Male ; Infant, Newborn ; Retrospective Studies ; Mutation ; Female ; Protein Tyrosine Phosphatases, Non-Receptor/genetics*

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

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

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

We report a first Korean case of presumably dominantly inherited primary tubular aggregate myopathy in a 19-yr-old man, who presented with slowly progressive proximal muscle stiffness and weakness. In hematoxylin and eosin stain, it showed subsarcolemmal, or central pale basophilic granular vacuoles, which stained red with modified Gomori's trichrome and intensive blue with nicotinamide adenonine dinucleotide-tetrazolium reductase, respectively. Ultrastructurally, aggregates of 60 nm-sized hexagonal tubules were found in both type 1 and type 2 fibers. We briefly review the pathologic findings of the previously reported cases of tubular aggregate myopathy and discuss the possible pathogenesis of this disease. We briefly discuss the possible pathogenesis of sarcoplasmic reticulum and review the ultrastructural characteristics.
Adult ; Biopsy ; Frozen Sections ; Genes, Dominant ; Genes, Recessive ; Human ; Korea ; Male ; Microscopy, Electron ; Microtubules/ultrastructure ; Mitochondria, Muscle/ultrastructure ; Muscle, Skeletal/pathology* ; Myopathies, Structural, Congenital/diagnosis ; Myopathies, Structural, Congenital/genetics ; Myopathies, Structural, Congenital/pathology* ; Pedigree