Congenital myopathy with cores

Congenital myopathy with cores is a group of inherited neuromuscular disorders characterized by the presence of areas of reduced oxidative activity (called 'cores') within muscle fibers, visible on muscle biopsy. This category encompasses several subtypes, including central core disease (CCD) and multiminicore disease (MmD), which are distinguished by the size, number, and distribution of cores within the muscle fibers. The skeletal muscular system is primarily affected, leading to muscle weakness that is often most prominent in the proximal muscles (those closest to the trunk), particularly the hip girdle and thigh muscles. Common clinical features include hypotonia (reduced muscle tone) at birth or in infancy, delayed motor milestones, facial weakness, and skeletal abnormalities such as hip dislocation, scoliosis, and foot deformities. Severity is highly variable, ranging from mild weakness compatible with independent ambulation to more severe forms with respiratory insufficiency requiring ventilatory support. The most commonly implicated gene is RYR1, encoding the ryanodine receptor 1, which plays a critical role in calcium release during muscle contraction. Mutations in SELENON (formerly SEPN1), MYH7, and other genes can also cause core myopathies. Importantly, RYR1-related core myopathies carry a risk of malignant hyperthermia susceptibility, a potentially life-threatening reaction to certain anesthetic agents, which must be communicated to all healthcare providers. Inheritance can be autosomal dominant (most commonly in central core disease) or autosomal recessive (more frequently seen in multiminicore disease and some RYR1-related forms). There is currently no curative treatment for congenital myopathy with cores. Management is supportive and multidisciplinary, including physical therapy to maintain mobility and prevent contractures, orthopedic interventions for skeletal complications, respiratory monitoring and support when needed, and careful anesthetic precautions. Regular cardiac screening may be recommended in certain genetic subtypes. Research into targeted therapies is ongoing, and genetic counseling is recommended for affected individuals and their families.

Common questions about Congenital myopathy with cores