LAMB3 is a laminin that belongs to a family of basement membrane proteins. This protein is a beta subunit laminin, which together with an alpha and a gamma subunit, forms laminin-5. Mutations in this gene cause epidermolysis bullosa junctional Herlitz type, and generalized atrophic benign epidermolysis bullosa, diseases that are characterized by blistering of the skin. Multiple alternatively spliced transcript variants that encode the same protein have been found for this gene.LAMb3 is approximately 29 kb long and consists of 23 exons that vary from 64 to 379 basepairs, accounting for the full-length cDNA with an open reading frame of 3,516 bp encoding 1,172 amino acids. In comparison with the LAMB1 gene, LAMB3 is considerably more compact.