Laminin is a heterotrimeric extracellular matrix protein consisting of 3 chains: alpha-1,beta-1 and gamma-1, formerly called beta-2 (LAMA2). This gene is over 260, 000 base pairs and contains 64 exons. Laminin is similar with merosin, a basement membrane-associated protein found in placenta, striated muscle, and peripheral nerve, and both of them are members of the same family of basement membrane proteins. And merosin is the same as laminin M, a striated muscle-specific, basal-lamina-associated protein, it may play a primary role in the pathogenesis of that disorder.