Amelogenin, X isoform is a protein that in humans is encoded by the AMELX gene. [3] AMELX is located on the X chromosome and encodes a set of isoforms of amelogenin by alternative splicing. [4] [5] Amelogenin is an extracellular matrix protein involved in the process of amelogenesis, the formation of enamel on teeth.
AMELX is involved in biomineralization during tooth enamel development. [6] The AMELX gene encodes for the structural modeling protein, amelogenin, which works with other amelogenesis-related proteins to direct the mineralisation of enamel. This process involves the organization of enamel rods, the basic unit of tooth enamel, as well as the inclusion and growth of hydroxyapatite crystals.
Mutations in AMELX result in amelogenesis imperfecta. [7] It has been shown that mice with a knocked-out AMELX gene will present disorganized and hypoplastic enamel. [8]
Ameloblasts are cells present only during tooth development that deposit tooth enamel, which is the hard outermost layer of the tooth forming the surface of the crown.
Amelogenins are a group of protein isoforms produced by alternative splicing or proteolysis from the AMELX gene, on the X chromosome, and also the AMELY gene in males, on the Y chromosome. They are involved in amelogenesis, the development of enamel. Amelogenins are type of extracellular matrix protein, which, together with ameloblastins, enamelins and tuftelins, direct the mineralization of enamel to form a highly organized matrix of rods, interrod crystal and proteins.
Enamelin is an enamel matrix protein (EMPs), that in humans is encoded by the ENAM gene. It is part of the non-amelogenins, which comprise 10% of the total enamel matrix proteins. It is one of the key proteins thought to be involved in amelogenesis. The formation of enamel's intricate architecture is thought to be rigorously controlled in ameloblasts through interactions of various organic matrix protein molecules that include: enamelin, amelogenin, ameloblastin, tuftelin, dentine sialophosphoprotein, and a variety of enzymes. Enamelin is the largest protein (~168kDa) in the enamel matrix of developing teeth and is the least abundant of total enamel matrix proteins. It is present predominantly at the growing enamel surface.
Ameloblastin is an enamel matrix protein that in humans is encoded by the AMBN gene.
Dentinogenesis imperfecta (DI) is a genetic disorder of tooth development. It is inherited in an autosomal dominant pattern, as a result of mutations on chromosome 4q21, in the dentine sialophosphoprotein gene (DSPP). It is one of the most frequently occurring autosomal dominant features in humans. Dentinogenesis imperfecta affects an estimated 1 in 6,000-8,000 people.
Amelogenin, Y isoform is a protein that in humans is encoded by the AMELY gene. AMELY is located on the Y chromosome and encodes a form of amelogenin. Amelogenin is an extracellular matrix protein involved in biomineralization during tooth enamel development.
Biomimetic materials are materials developed using inspiration from nature. This may be useful in the design of composite materials. Natural structures have inspired and innovated human creations. Notable examples of these natural structures include: honeycomb structure of the beehive, strength of spider silks, bird flight mechanics, and shark skin water repellency. The etymological roots of the neologism "biomimetic" derive from Greek, since bios means "life" and mimetikos means "imitative".
Kallikrein-related peptidase 4 is a protein which in humans is encoded by the KLK4 gene.
Transcription factor Sp7, also called osterix (Osx), is a protein that in humans is encoded by the SP7 gene. It is a member of the Sp family of zinc-finger transcription factors It is highly conserved among bone-forming vertebrate species It plays a major role, along with Runx2 and Dlx5 in driving the differentiation of mesenchymal precursor cells into osteoblasts and eventually osteocytes. Sp7 also plays a regulatory role by inhibiting chondrocyte differentiation maintaining the balance between differentiation of mesenchymal precursor cells into ossified bone or cartilage. Mutations of this gene have been associated with multiple dysfunctional bone phenotypes in vertebrates. During development, a mouse embryo model with Sp7 expression knocked out had no formation of bone tissue. Through the use of GWAS studies, the Sp7 locus in humans has been strongly associated with bone mass density. In addition there is significant genetic evidence for its role in diseases such as Osteogenesis imperfecta (OI).
B-cell CLL/lymphoma 9 protein is a protein that in humans is encoded by the BCL9 gene.
Matrix metalloproteinase-20 (MMP-20) also known as enamel metalloproteinase or enamelysin is an enzyme that in humans is encoded by the MMP20 gene.
Enamel hypoplasia is a defect of the teeth in which the enamel is deficient in quantity, caused by defective enamel matrix formation during enamel development, as a result of inherited and acquired systemic condition(s). It can be identified as missing tooth structure and may manifest as pits or grooves in the crown of the affected teeth, and in extreme cases, some portions of the crown of the tooth may have no enamel, exposing the dentin. It may be generalized across the dentition or localized to a few teeth. Defects are categorized by shape or location. Common categories are pit-form, plane-form, linear-form, and localised enamel hypoplasia. Hypoplastic lesions are found in areas of the teeth where the enamel was being actively formed during a systemic or local disturbance. Since the formation of enamel extends over a long period of time, defects may be confined to one well-defined area of the affected teeth. Knowledge of chronological development of deciduous and permanent teeth makes it possible to determine the approximate time at which the developmental disturbance occurred. Enamel hypoplasia varies substantially among populations and can be used to infer health and behavioural impacts from the past. Defects have also been found in a variety of non-human animals.
Dentin sialophosphoprotein is a precursor protein for other proteins found in the teeth. It is produced by cells (odontoblasts) inside the teeth, and in smaller quantities by bone tissues. It is required for normal hardening (mineralisation) of teeth. During teeth development, it is broken down into three proteins such as dentin sialoprotein (DSP), dentin glycoprotein (DGP), and dentin phosphoprotein (DPP). These proteins become the major non-collagenous components of teeth. Their distribution in the collagen matrix of the forming dentin suggests these proteins play an important role in the regulation of mineral deposition. Additional evidence for this correlation is phenotypically manifested in patients with mutant forms of dentin sialophosphoprotein. Such patients suffer dental anomalies including type III dentinogenesis imperfecta.
FAM83H is a protein, which in humans is encoded by the FAM83H gene. The protein is also known as uncharacterized protein FAM83H. FAM83H is targeted for the nucleus. It is predicted to play a role in the structural development and calcification of tooth enamel.
Amelogenesis imperfecta (AI) is a congenital disorder which presents with a rare abnormal formation of the enamel or external layer of the crown of teeth, unrelated to any systemic or generalized conditions. Enamel is composed mostly of mineral, that is formed and regulated by the proteins in it. Amelogenesis imperfecta is due to the malfunction of the proteins in the enamel as a result of abnormal enamel formation via amelogenesis.
FAM20A is a protein that in humans is encoded by the FAM20A gene.
Jalili syndrome is a genetic disorder characterized by the combination of cone-rod dystrophy of the retina and amelogenesis imperfecta. It was characterized in 1988 by Dr. I. K. Jalili and Dr. N. J. D. Smith, following the examination of 29 members of an inbred Arab family living within the Gaza Strip.
Kohlschütter-Tönz syndrome (KTS), also called amelo-cerebro-hypohidrotic syndrome, is a rare inherited syndrome characterized by epilepsy, psychomotor delay or regression, intellectual disability, and yellow teeth caused by amelogenesis imperfecta. It is a type A ectodermal dysplasia.
Tricho–dento–osseous syndrome (TDO) is a rare, systemic, autosomal dominant genetic disorder that causes defects in hair, teeth, and bones respectively. This disease is present at birth. TDO has been shown to occur in areas of close geographic proximity and within families; most recent documented cases are in Virginia, Tennessee, and North Carolina. The cause of this disease is a mutation in the DLX3 gene, which controls hair follicle differentiation and induction of bone formation. All patients with TDO have two co-existing conditions called enamel hypoplasia and taurodontism in which the abnormal growth patterns of the teeth result in severe external and internal defects. The hair defects are characterized as being rough, course, with profuse shedding. Hair is curly and kinky at infancy but later straightens. Dental defects are characterized by dark-yellow/brownish colored teeth, thin and/or possibly pitted enamel, that is malformed. The teeth can also look normal in color, but also have a physical impression of extreme fragility and thinness in appearance. Additionally, severe underbites where the top and bottom teeth fail to correctly align may be present; it is common for the affected individual to have a larger, more pronounced lower jaw and longer bones. The physical deformities that TDO causes become more noticeable with age, and emotional support for the family as well as the affected individual is frequently recommended. Adequate treatment for TDO is a team based approach, mostly involving physical therapists, dentists, and oromaxillofacial surgeons. Genetic counseling is also recommended.
Sodium/potassium/calcium exchanger 4 also known as solute carrier family 24 member 4 is a protein that in humans is encoded by the SLC24A4 gene.
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