Human hereditary enamel abnormalities – molecular factors and genetic counselling

Abstract

Defective enamel formation may result either from factors of environmental origin or from genetic abnormality. Such genetically determined enamel malformations have been described in patients with chromosomal anomalies and with inherited single gene defects. Enamel is a principal component of the dentition, and defects in this hard tissue are associated with a wide variety of diseases. Dental enamel is the epithelial-derived hard tissue covering the crowns of teeth. It is the most highly mineralized and hardest tissue in the body. Dental enamel is acellular and has no physiological means of repair. Amelogenesis imperfecta (AI) is a group of genetically and phenotypically diverse forms of defective tooth enamel development. Progress has been made regarding the definition of the genetic basis of AI, but the exact mechanism for the biomineralization process remains largely unknown. The list of genes associated with enamel defects has grown tremendously over the past decade. The molecular pathways involved in the development of enamel defects are diverse, and the functionality of the genes and gene products is heterogeneous. Syndrome-associated enamel defects are caused by many genes that affect other tissues, including eye, kidney, brain, and skin. As with enamel defects, early diagnosis and preventive care are essential for successful management of dentine defects. Patients who have a family history of dentine defects such as dentinogenesis imperfecta or those with medical conditions known to be associated with dentine defects such as hypophosphataemia and osteogenesis imperfecta should be screened early for dental problems.