amelogenesis imperfecta, a condition characterized by brown or white chalky discoloration of the teeth and resulting from either severe enamel hypocalcification or enamel hypoplasia. The condition, which is inherited as an autosomal-dominant trait, is classified according to severity: in agenesis, there is a complete lack of enamel; in enamel hypoplasia, defective matrix formation causes the enamel to be normal in hardness but deficient in quantity; and in enamel hypocalcification, defective maturation of ameloblasts results in enamel that is normal in quantity but soft and undercalcified. Also called hereditary brown enamel, hereditary enamel hypoplasia. Compare dentinogenesis imperfecta.
