Laminin subunit alpha 2-related muscular dystrophy

Laminin subunit alpha 2-related muscular dystrophy (LAMA2-related muscular dystrophy), also known as merosin-deficient congenital muscular dystrophy type 1A (MDC1A) or LAMA2-related dystrophy, is a rare genetic neuromuscular disorder caused by pathogenic variants in the LAMA2 gene, which encodes the laminin alpha-2 chain (also called merosin). This protein is a critical component of the extracellular matrix in skeletal muscle, Schwann cells, and the brain. The disease primarily affects the skeletal muscular system but can also involve the central and peripheral nervous systems. The clinical spectrum ranges from a severe, early-onset congenital muscular dystrophy (complete merosin deficiency) to a milder, later-onset limb-girdle phenotype (partial merosin deficiency). In the severe form, which is the most common presentation, infants present at birth or within the first few months of life with profound hypotonia ("floppy baby"), severe muscle weakness, poor spontaneous movements, feeding difficulties, and respiratory insufficiency. Most children with the severe form never achieve independent ambulation. Characteristic white matter abnormalities are seen on brain MRI, though intellectual disability is not always present. Joint contractures develop progressively, and scoliosis is common. Seizures occur in a subset of patients (approximately 20-30%). Peripheral neuropathy may also be present. Serum creatine kinase levels are typically markedly elevated. There is currently no cure or disease-modifying treatment for LAMA2-related muscular dystrophy. Management is supportive and multidisciplinary, including respiratory support (non-invasive ventilation or tracheostomy in severe cases), nutritional support (sometimes requiring gastrostomy), physical therapy to manage contractures, orthopedic interventions for scoliosis, and seizure management when needed. Early and proactive respiratory care has significantly improved survival. Gene therapy and other molecular approaches are under investigation in preclinical studies.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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