The MMP20 protein belongs to the matrix metalloproteinase (MMP) family of proteins. These proteins are involved in the breakdown of extracellular matrix in normal processes, such as embryonic development, reproduction, and tissue remodeling. The MMP20 gene codes for a tooth-specific matrix metalloproteinase-20, which functions by degrading amelogenin, which is the major protein component of dental enamel matrix. Therefore, mutations in this gene contribute to the abnormal formation of tooth enamel. This gene is expressed in secretory stage ameloblasts, and the expressed protein plays a major role in allowing the enamel crystallites to grow in width and thickness. MMP20 might also play a role in facilitating ameloblast movement in rows necessary to form mammalian rod patterns.
Mutations in MMP20 are implicated in a form of Amelogenesis Imperfecta (AI2A2) as well as in age related macular degeneration.