Diseases with hereditary predisposition
diseases with hereditary predisposition have differences of gene diseases that are in need of influence on the human body of environmental factors to the disease appeared.According to the genetic nature of diseases with hereditary predisposition divided into 2 groups.
1. monogenic diseases with hereditary predisposition.
This group of diseases characterized by the fact that the predisposition is determined only by one gene, ie. E. It is associated with a mutation of the gene.It includes: neurofibromatosis, Marfan syndrome, familial hypercholesterolaemia, osteogenesis imperfecta, atrophic myotonia, achondroplasia, adenomatous polyposis colon cancer, Huntington's disease, polycystic kidney disease, cystic fibrosis, hemoglobinopathies.For the manifestation of symptoms of the disease must be compulsory exposure to environmental factors.This factor usually accurately identified and in relation to the disease is regarded as specific.
2. Polygenic diseases with hereditary predisposition.
This group of diseases is determined by multiple genes, each of which is more normal than the pathological changes.The identification of these genes is a difficult task.It includes: diabetes mellitus, gout, cleft lip, cleft palate, which are run in families.His pathological manifestation they carry out in cooperation with a whole set of environmental factors.Such diseases are called multifactorial, t. E. Develop under the influence of many factors, both external and internal.The relative role of genetic factors and environmental factors are different, not only for this disease, but also for each individual case of disease.
These features make these diseases are different and genetically, and significance in human pathology.The first group of relatively rare diseases, are applicable to them Mendelian genetic analysis techniques, their prevention and treatment sufficient certainty and, in some cases effective.Given the central role of the medium in their manifestation, these hereditary diseases are considered as arising from pathological reactions to external effect factors.
multifactorial diseases account for 90% of chronic non-communicable diseases of various systems and organs.Analysis of these diseases to clarify the role of individual genes and their interaction with environmental factors is very difficult, so in the treatment and prevention of genetics has not yet made a significant contribution.
In this particular disease is multifactorial complexity of genetic analysis, limited clinical-genealogical and twin methods of research, the need for complex mathematical and biological techniques to elucidate the role of specific genes and environmental factors in the development of these diseases.Numerous materials and genealogical twin analyzes, accumulated over the years of study of diseases with hereditary predisposition, show only about the meaning of heredity in the occurrence of the disease, but does not decode any gene or the type of transmission.
Of the features of the development of multifactorial diseases should be a wide variety of manifestations of the subtle and hidden forms even before the heavy flowing and hard-to-therapy.The diversity of the genetic basis of each disease based on the individuality of each organism, helps to explain such features of multifactorial diseases such as variability (even within the same family) the age of onset of the disease, its development, the spectrum of manifestations of the disease and the degree of their severity.With these features are also related to significant differences in the incidence of various diseases and their forms within a population.