THE ROLE OF GENES AND ENVIRONMENT IN THE DEVELOPMENT OF PROGENIC FORMS OF BITE (REVIEW)

The development of dental-maxilla apparatus, as well as the development of other organs, is influenced by two main groups of factors: internal (genotype) - this factor seeks to realize inherent in the development programme of the authority with the smallest possible number of deviations, depending on various extraneous influences, and external factors physiological and pathogenic. These factors are aimed at changing body that grows in accordance with the external conditions. The effect of physiological factors wearing corrective, guiding character, and the action of pathogen - deforming, destructive. The interaction of these two groups determines the final outcome is a phenotype [1-3]. Genetic and environmental factors play an important role in the etiology of malocclusion, while the final phenotypic expression is the result of the influence of both these factors, the undeniable proof is a genetic influence on the majority of dental and occlusal variations [4]. Merging into one group of physiological and pathogenic factors is due to the fact that clear boundaries between them often do not exist. Depending on individual sensitivity to specific factors, and quantitative characteristics of its physiological role can be transformed into pathogenic. The groups of external factors capable of carrying out physiological or pathological effect on the development of dentoalveolar apparatus can be summarized as follows: functional factors (poor oral pathology of muscles of the maxillofacial region), the impact of various diseases (rickets, etc.), environmental and external influences. Almost always there are several factors that determine each other and thus connected into a single pathogenetic chain. Typical malocclusions are a typical example of the interaction of hereditary factors and the influence of environmental factors [5, 1, 2, 6]. In this respect, a clear example of progenic forms occlusion. Occurrence is divided into acquired and congenital. The latter, in turn, are divided into hereditary and non-hereditary. Almost 17-21% of all registered anomalies of the jaw complex are genetically were determined, others can be considered acquired [7]. Hereditary malocclusion is observed in several generations, with "transmitted" complete or partial syndrome of characteristics. Congenital not hereditary progeny, according to many scientists, arise as a result of mechanical factors, in particular in the embryonic period of development, abnormal position of the fetus, during birth, toxoplasmosis, etc. Today, there are numerous molecular-genetic studies to find possible candidate genes involved in the formation progenic forms of occlusion. Progress in molecular biology, as emphasized by the authors, has allowed the recognition of different genes involved in the growth of the lower jaw. A large number of genes described as key regulatory factors contributing to the growth of condyle (articular head) under the action of mechanical stress, and these genes may play an important role in the development of "Class III" malocclusion. Recent genetic studies using analysis of coupling and associative studies have extended the range of genes responsible for the formation of "Class III" malocclusion. Recent studies have reported that genes that encode specific growth factors or other signaling molecules are involved in condylar growth under mechanical strain. These genes, which include Indian hedgehog homolog (IHH), parathyroid-hormone like hormone (PTHLH), insulin-like growth factor- 1 (IGF-1), and vascular endothelial growth factor (VEGF), and variations in their levels of expression play an important role in the etiology of "Class III" malocclusion. The polygenic nature of inheritance, to search for new candidate genes, leads to use modern molecular genetic technologies, in particular GWAS (Genome-Wide Association Study) for genome wide Association studies, which is a new and very powerful tool that scientists beginning to use for identify a genetic contribution to the phenotype [6]. Thus, the "Class III" malocclusion is the result of several factors interacting in morphogenetic period of development of the lower jaw, and you can adjust some of these factors in childhood. Based on this, provides a better understanding of the genetic changes, which in some way lead to the phenotype of Class III that requires the need to develop new strategies for the prevention of this condition. Such approaches will allow the doctor to choose early and timely oral and maxillofacial and orthodontic treatment aimed at preventing the development of "Class III" malocclusion. Therefore, further research in this direction remain very relevant