Gene mutations - that is the reason for which is the formation of a heterogeneous group of clinical manifestations of disease, which is called "genetic disease".The overall frequency of their occurrence in the human population by two to four percent.
change (mutation) genes is provoking the development of many forms of hereditary diseases factor.In modern medicine, described more than three thousand of these pathologies.The most common manifestation of the disease is fermentopathy.It is believed that the mutations may affect embryonic, transport and structural proteins.Pathological changes can be implemented in different stages of ontogeny (development).Most of them are characterized by intrauterine (up to 25% of all hereditary diseases) and dopubertatnogo (before puberty) period (45%).Gene mutations occur in adolescence (puberty), and adolescence (about 25%).The relatively small amount (about 10%) lesions detected over twenty years.
Hereditary diseases are classified according to the type of inheritance (autosomal recessive, autosomal dominant, etc.), depending on the organ or system, more involved in the pathological process (endocrine, neuromuscular, eye, etc.), taking into account the nature of the metabolicdeficiency (associated with a disorder of carbohydrate, mineral and other lipid metabolism.).For self group includes diseases that have arisen against the background of the incompatibility of the fetus and the mother of the antigens in the blood groups.
Provoked germline mutations, inherited disease, in accordance with the laws of Mendel.Perhaps the emergence of new development or inherited from past generations change.In such cases, pathological structures distributed in all body cells.
Arise gene mutations may be in one of the cells at different stages of crushing zygote.In such cases, the body becomes the mosaic for the structure.In other words, in some cells, normal functioning allele (form of the gene), and in others - mutant.Domination mutation manifested phenotypically (clinical signs) in the corresponding cells and triggers the development of the disease.At the same time there is a sufficient likelihood of less severe disease, as opposed to the full mutants.
Experts classify changes in the functional and structural changes.
structural gene mutations are divided into transitions - the replacement of a purine base (natural organic compounds, purine derivatives) to another, or one pyrimidine base (organic compounds - pyrimidine derivatives) to another pyrimidine base;at the same codon (unit of genetic code) changes only one in which there was a replacement.There is also such a thing as "transversion".In this case there is a replacement of the purine or pyrimidine bases, on the contrary.This also changes the codon in which case the replacement.Furthermore, there is a frameshift mutation.Thus there is a loss of (deletion) or insertion (insertion) or a multiple of one base pair.In accordance with the site or the insertion loss can be varied more or fewer codons.
Mutations in genes are functional change nontranscribed (encoding) part of the DNA molecule.This provokes a disorder of regulation of the functioning of the structural elements.This may result in increase or decrease in the rate of synthesis of the corresponding protein to varying degrees.
