ENAM

The ENAM gene provides instructions for making a protein called enamelin, which is essential for normal tooth development. Enamelin is involved in the formation of enamel, which is the hard, white material that forms the protective outer layer of each tooth. Enamel is composed mainly of mineral-containing crystals. These microscopic crystals are arranged in organized bundles that give enamel its strength and durability. Although the exact function of enamelin is not well understood, this protein plays a key role in the formation and growth of crystals in developing enamel.

amelogenesis imperfecta - caused by mutations in the ENAM gene

At least seven mutations in the ENAM gene have been identified in people with autosomal dominant forms of amelogenesis imperfecta. Autosomal dominant inheritance means that one copy of the ENAM gene in each cell is altered. Mutations in the ENAM gene have a variety of effects on enamel formation. Some mutations reduce the amount of enamelin produced by the gene. Other mutations lead to the production of an abnormally short version of enamelin that is missing critical regions. Altered or missing enamelin can lead to severe problems with developing enamel, or cause milder defects such as shallow pits or horizontal grooves in the teeth.

Mutations in the ENAM gene also have been found in people with an autosomal recessive form of amelogenesis imperfecta. Autosomal recessive inheritance means that two copies of the ENAM gene in each cell are altered. These mutations result in the production of an abnormal version of enamelin that prevents enamel from developing properly. People who inherit two mutated copies of the ENAM gene have severe defects in their enamel; as a result, this protective covering may be very thin or completely absent.