International Journal of Science and Research (IJSR) ISSN (Online): 2319-7064 Index Copernicus Value (2015): 78.96 | Impact Factor (2015): 6.391 Volume 6 Issue 4, April 2017 www.ijsr.net Licensed Under Creative Commons Attribution CC BY Amelogenesis Imperfecta in Children: Review of Pathogenetic Aspect Harun Achmad 1 , Hasanuddin Thahir 2 , Mardiana Adam 3 1 Department of Pediatric Dentistry, Faculty of Dentistry Hasanuddin University 2, 3 Department of Periodontolgy, Faculty of Dentistry Hasanuddin University Abstract: Amelogenesis imperfecta is an abnormal formation of the enamel. This anomaly associated with malformation of proteins, such as ameloblastin, enamelin, tuftelin and amelogenin. A few study report, mutation in the AMELX, ENAM, MMP20 and KLK-4 genes have been found to cause amelogenesis imperfecta. Mutations of AMELX, ENAM, MMP20 and KLK-4 genes will alter the structure of protein, that are essential for normal tooth development. People with amelogenesis imperfecta have teeth with abnormal color; yellow, brown or grey and have a higher risk for dental caries and hypersentive to temperature changes. Incidence of amelogenesis imperfecta estimated 1 per 14.000 people in USA and 1 per 700 people in Northern Sweden. The purpose of this paper is to describe of pathology of amelogenesis imperfecta and its management. The treatment depends on severity of the problem. Full crowns will improve the appearance of the teeth and protect them from damage. Keywords: Amelogenesis Imperfecta, mutation genes, full crown 1. Introduction Dental enamel is highest mineralized tissue in human body, consists of 85% hydroxyapatite crystals. This mineralized layer cannot be replaced or repaired. This crystals fulfill prism pattern given unique characteristic and fracture resistance properties for enamel. Development of unique mineral structure of enamel and its composition controlled by ameloblast. Ameloblast cells will disappear as tooth eruption. Enamel formation require some genes expression which record protein matrix and proteinase requirement for controlling growth process and mineralization of crystals. 1,2 X-linked amelogenesisimperfecta is a form of hereditary phenotypedamage which affects enamel development. This damage caused by gene mutation of human X chromosome. It is characterized by various phenotype in individual with hypoplastic damage and/or hypomineralization while enamel content decrease. Amelogenesisimperfecta associated with gene mutation indetified for determining involvement of two molecules of extracellular matrix of enamel, they are amelogenin and enamelin. Amelogenin is protein that produce AMELX Xq22 and AMELY Yp11 genes which fulfill 90% of organic matrix in enamel development, this protein considered as main protein for structure and thickness of enamel. Enamelin is a protein produce ENAM gene in 4q21 chromosome, present in low number and undergo a series of proteolytic breakdown to generate various polypeptides that plays a role in nucleation, regulation, and enamel crystal extention. Alel mutation of gene code of amelogenin and enamelin associated with different phenotype of amelogenesis imperfect, showing that these proteins provide important function during enamel formation. 1,2 Besides ENAM and AMELX, the number of other genes important for enamel formation has been identified and considered as cause of amelogenesis imperfecta, includes ameloblastin, tuftelin, and two genes for enamel proteinase, i.e. enamelisin (MMP-20) and kallikrein 4 (KLK-4). These proteinase contribute to protein matrix regulation which provide enamel structure and composition. Abnormal proteolytic protein matrix generates enamelconsidered as principle of developmental mechanisms associated with autosomal inherited forms of hypomaturationamelogenesis imperfecta. Teeth with autosomal recessive hypomaturation amelogenesis imperfecta, show defense amelogenin protein that supports proteinase or protein damage. MMP-20 activity causes hypoplastic and hypomineralization of enamel. 2 2. Literature Review Amelogenesis imperfecta (amelo: formation of enamel, imperfecta: imperfecta) is a disorder of tooth development, relatively rare inherited disorder group with abnormal formation of enamel. This condition causes tooth become small, discolored and damaged. These disorders varyamong affected individuals, can influence deciduous and permanent teeth. 3 Enamel disorder amelogenesis imperfectawidely vary and classified as hypoplasia (abnormality inamount of enamel), hypomaturation (abnormalities in growth and maturation of the enamel crystal), and hypocalcification (abnormalities in initial crystal formation followed by growth disturbance). Enamel both in amelogenesis imperfecta of hypomaturation and hypocalcification types not mineralized to normal level of enamel and can be described as hipomineralization. Amelogenesis imperfecta can be inherited as an autosomal recessive X-linked or autosomal dominant. Incidence of amelogenesis imperfecta is uncertain, with widely vary estimates, 1 in 700 people in northern Sweden, to 1 in 14,000 people in the United States. 4 Mutations of AMELX, ENAM, and MMP20 genes cause amelogenesis imperfecta. AMELX, ENAM, MMP20 give instructions in forming essential protein for tooth development. This protein is involved in enamel formation which is hard material, rich in calcium, forming protective outer layer of each tooth. Mutations in one gene alter the structure of this protein, consequently enamel becomes Paper ID: ART20172791 DOI: 10.21275/ART20172791 2366