Ameloblastin
Ameloblastin (abbreviated AMBN and also known as Sheathlin or Amelin) is an enamel matrix protein that in humans is encoded by the AMBN gene. Function. Ameloblastin, also known as amelin, is a gene-specific protein found in tooth enamel. Although less than 5% of enamel consists of protein, ameloblastins comprise 5–10% of all enamel protein. This protein is formed by ameloblasts during the early secretory to late maturation stages of amelogenesis. Although not completely understood, the function of ameloblastins is believed to be in controlling the elongation of enamel crystals and generally directing enamel mineralization during tooth development. Other  significant proteins in enamel are amelogenins, enamelins, and tuftelins. This gene encodes the nonamelogenin enamel matrix protein ameloblastin. The encoded protein may be important in enamel matrix formation and mineralization. This gene is located in the calcium-binding phosphoprotein gene cluster on chromosome 4. Mutations in this gene may be associated with dentinogenesis imperfecta and autosomal dominant amelogenesis imperfecta. [provided by RefSeq, Aug 2011]. Clinical significance. Mutations in AMBN cause amelogenesis imperfecta.