Laminin subunit alpha 2-related congenital muscular dystrophy

Laminin subunit alpha 2-related congenital muscular dystrophy (LAMA2-related CMD), also known as merosin-deficient congenital muscular dystrophy (MDC1A) or LAMA2-related muscular dystrophy, is a rare genetic neuromuscular disorder caused by mutations in the LAMA2 gene, which encodes the laminin alpha-2 chain (also called merosin). Laminin alpha-2 is a critical structural protein in the extracellular matrix surrounding muscle fibers, Schwann cells in peripheral nerves, and brain tissue. Deficiency or dysfunction of this protein leads to progressive skeletal muscle weakness and wasting, primarily affecting the musculoskeletal and nervous systems. The disease typically presents at birth or within the first few months of life with severe hypotonia (low muscle tone), poor spontaneous movements, feeding difficulties, and respiratory insufficiency. Affected children often have delayed motor milestones, and many never achieve independent ambulation. Joint contractures are common and progressive. A hallmark finding on brain MRI is diffuse white matter abnormalities, although intellectual function is often preserved or only mildly affected. Seizures occur in a subset of patients (approximately 20-30%). Peripheral neuropathy may also be present. Elevated serum creatine kinase (CK) levels are a consistent laboratory finding. A milder, partial merosin-deficient phenotype exists, where patients may achieve ambulation and have a later onset of symptoms with slower progression. There is currently no cure for LAMA2-related CMD. Management is supportive and multidisciplinary, focusing on respiratory care (including non-invasive ventilation when needed), nutritional support, physical therapy to manage contractures, orthopedic interventions such as scoliosis surgery, and seizure management when applicable. Cardiac involvement is uncommon but should be monitored. Research into gene therapy and other molecular approaches is ongoing but remains in early stages. Early intervention and coordinated care can significantly improve quality of life and survival.

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