Centronuclear myopathy arises from inherited pathogenic variants in genes encoding proteins essential to skeletal muscle cell organization and membrane dynamics. The specific gene names verified in this packet's known_genes field are not populated; the causal gene information available comes from the GeneReviews source entry. GeneReviews characterization of the X-linked myotubular form indicates inheritance follows an X-linked pattern, with males carrying a single pathogenic copy expressing the full disease phenotype. Among identified variant types in this X-linked form, nonsense and frameshift alterations — which predict loss of protein function — nearly always produce the severe classic phenotype. Splice site and intronic variants may yield either severe or milder presentations. Missense variants span a range of severity from severe to mild or moderate phenotypes, with pathogenic variants distributed throughout the gene without concentration in any specific domain. Disease subtypes within the broader centronuclear myopathy group include forms with autosomal recessive inheritance. Penetrance in males with the X-linked form is considered essentially complete, as all documented individuals with pathogenic variants exhibit disease findings, though severity varies considerably.

Diagnosis of centronuclear myopathy relies on a combination of clinical, histopathological, and molecular findings. Clinical indicators in the X-linked myotubular form include neonatal hypotonia, respiratory failure, diffuse muscle weakness, and a family history consistent with X-linked inheritance in male neonates. Ophthalmoparesis is a particularly informative feature distinguishing X-linked myotubular myopathy from some overlapping congenital myopathies. Muscle biopsy is central to histopathological diagnosis, demonstrating the characteristic central placement of myonuclei with nuclear-predominance patterns. Molecular genetic testing identifies the specific pathogenic variant and confirms subtype classification. Evaluations following initial diagnosis, as described in GeneReviews for the X-linked form, include assessment of pulmonary function for long-term ventilatory planning, feeding and swallowing assessment by qualified specialists, and ophthalmologic evaluation. Disorders in the differential diagnosis include congenital myotonic dystrophy type 1, other centronuclear myopathy subtypes with autosomal inheritance (including those associated with DNM2), and additional congenital myopathies with overlapping histopathological findings.

No pharmacologic agents are listed in this packet's approved treatments or foundational therapies fields for centronuclear myopathy. Management of the X-linked myotubular form, as described in GeneReviews, centers on multidisciplinary supportive care involving pulmonology, neurology, physical therapy, rehabilitation medicine, and clinical genetics. Ventilatory management is a central concern, with long-term respiratory support determined on an individual basis. Feeding and swallowing difficulties may require nutritional support interventions involving occupational therapy or equivalent allied health professionals. In anesthetic planning for individuals with the X-linked myotubular form, neuromuscular paralytics including succinylcholine are generally not employed; however, the X-linked form does not carry susceptibility to malignant hyperthermia. Gene replacement therapy strategies using adeno-associated viral (AAV) delivery of the functional gene copy are under active investigation in clinical trials. GeneReviews documents that AAV-mediated gene delivery has produced significant improvement in strength, histopathology, and survival in both murine and canine preclinical models. Additional investigational strategies targeting disease modifier pathways through antisense oligonucleotide-mediated approaches are in preclinical development. Multiple active clinical trials in this packet explore gene-based and other therapeutic approaches.

Disease course in centronuclear myopathy is highly variable and depends on subtype and severity. In the severe classic X-linked myotubular form, chronic ventilator dependence and significant functional limitations are characteristic of the long-term course. GeneReviews penetrance data indicates that essentially all males with the X-linked form exhibit disease findings, though severity ranges from severe to mild or moderate. Ongoing monitoring for individuals with the X-linked form, as documented in GeneReviews, encompasses annual pulmonary assessment with pulmonary function testing, polysomnography every one to three years, spinal examination for scoliosis particularly in late childhood and adolescence, and annual ophthalmologic evaluation addressing ophthalmoplegia, ptosis, myopia, and eyelid closure function. Dental malocclusion may require orthodontic evaluation over time. Natural history data for the broader centronuclear myopathy spectrum — including autosomal recessive subtypes — is not available in this packet beyond the X-MTM GeneReviews characterization.

Multiple clinical trials are active in centronuclear myopathy, with particular focus on the X-linked myotubular form. Trials in this packet include a Phase I/II study of AT132 in young children with X-linked myotubular myopathy (NCT03199469, Astellas Gene Therapies, active not recruiting) and additional studies exploring AAV-mediated gene replacement and investigational agents. GeneReviews notes that several investigational strategies targeting disease modifier pathways — including approaches to lower a key modifier protein using antisense oligonucleotide methods — have shown promise in preclinical models of X-linked myotubular myopathy. The clinical trial portfolio in this packet also includes observational and interventional studies spanning pediatric and young adult populations with this subtype.