Congenital muscular dystrophy type 1B (MDC1B) is a rare, inherited disorder that affects the muscles and nervous system. It is characterized by progressive muscle weakness, joint contractures, and respiratory problems. It is caused by mutations in the laminin alpha-2 gene, which is responsible for producing a protein that helps to form the structural framework of muscle cells. Symptoms usually appear in infancy or early childhood and can include hypotonia (low muscle tone), muscle weakness, joint contractures, and respiratory problems. Other features may include scoliosis, facial weakness, and intellectual disability. Treatment is supportive and may include physical therapy, occupational therapy, and respiratory support.