Genic diseases are called heterogeneous in clinical manifestations of a group of diseases that occur under the influence of mutations at the gene level. A group of hereditary gene diseases that arise and develop against the background of a defect in the hereditary apparatus of cells and the influence of adverse environmental factors should be considered separately.
What are multifactorial hereditary diseases
Specifically, this group of diseases has one clear difference from gene diseases. Multifactorial diseases begin to manifest themselves under adverse environmental factors. Some scientists suggest that a genetic predisposition may never manifest unless environmental factors arise.
The etiology and genetics of multifactorial diseases is very complex, the origin has a multi-stage structure and may be different in the case of each specificdisease.
Varieties of multifactorial pathologies
Conditionally multifactorial hereditary diseases can be divided into:
- native malformations;
- diseases of a mental and nervous nature;
- age-related diseases.
Depending on the number of genes involved in pathology, they distinguish:
- Monogenic diseases - have one mutant gene, which creates a person's predisposition to a particular disease. In order for the disease in this case to begin to develop, it will be necessary to influence one specific environmental factor. It can be physical, chemical, biological, or medicinal. If a specific factor has not arisen, even if the mutant gene is present, the disease will not develop. If a person does not have a pathogenic gene, but is exposed to an external environmental factor, the disease will not occur either.
- Polygenic hereditary diseases or multifactorial diseases are determined by pathologies in many genes. The action of multifactorial signs can be discontinuous or continuous. But any of the diseases can only arise through the interaction of many pathogenic genes and environmental factors. Normal human characteristics, such as intelligence, height, weight, skin color, are continuous multifactorial traits. Isolated congenital malformations (cleft lips and palate), congenital heart disease, neur altubes, polyrostenosis, hypertension, peptic ulcer disease and some others have a higher incidence in close relatives than in the general population. Multifactorial diseases, examples of which are mentioned above, are "intermittent" multifactorial features.
Diagnostic MFZ
Different types of studies help diagnose multifactorial diseases and the role of genetic heredity. For example, a family study, thanks to which the concept of an “oncological family” appeared in the practice of doctors, that is, a situation where repeated cases of malignant diseases occur in relatives within the same pedigree.
Doctors often resort to the study of twins. This method, like no other, allows you to operate with reliable data on the hereditary nature of the disease.
Studying multifactorial diseases, scientists pay a lot of attention to the study of the relationship between the disease and the genetic system, as well as the analysis of the pedigree.
IHF-specific criteria
- The degree of relationship directly affects the likelihood of manifestation of the disease in relatives, that is, the closer the relative is to the patient (in genetic terms), the greater the likelihood of the disease.
- The number of patients in the family affects the risk of the disease in relatives of the patient.
- The severity of the disease of the affected relative affects the genetic prognosis.
Diseases related toto multifactorial
Multifactorial diseases include:
- Bronchial asthma is a disease based on chronic allergic inflammation of the bronchi. It is accompanied by hyperactivity of the lungs and the periodic occurrence of attacks of shortness of breath or suffocation.
- Peptic ulcer, which is a chronic relapsing disease. It is characterized by the formation of ulcers in the stomach and duodenum due to disturbances in the general and local mechanisms of the nervous and humoral systems.
- Diabetes mellitus, in the process of which both internal and external factors are involved, causing disturbances in carbohydrate metabolism. The occurrence of the disease is strongly influenced by stress factors, infections, injuries, operations. Risk factors may include viral infections, toxic substances, overweight, atherosclerosis, decreased physical activity.
- Ischemic heart disease is a consequence of a reduced or complete lack of blood supply to the myocardium. This happens due to pathological processes in the coronary vessels.
Prevention of multifactorial diseases
Types of preventive measures that prevent the occurrence and development of hereditary and congenital diseases can be primary, secondary and tertiary.
The primary type of prevention is aimed at preventing the conception of a sick child. This can be realized in the planning of childbearing and improving the human environment.
Secondary preventionis aimed at terminating the pregnancy if the likelihood of the disease in the fetus is high or the diagnosis has already been established prenatally. The basis for making such a decision may be a hereditary disease. Occurs only with the consent of the woman in a timely manner.
The tertiary type of prevention of hereditary diseases is aimed at combating the development of the disease in an already born child and its severe manifestations. This type of prevention is also called normocopying. What it is? This is the development of a he althy child with a pathogenic genotype. Normcopying with the appropriate medical complex can be done in utero or after birth.
Prevention and its organizational forms
Prevention of hereditary diseases is implemented in the following organizational forms:
1. Medical genetic counseling is a specialized medical care. Today, one of the main types of prevention of hereditary and genetic diseases. For medical genetic counseling please contact:
- he althy parents who gave birth to a sick child, where one of the spouses has a disease;
- families with practically he althy children, but who have relatives with hereditary diseases;
- parents seeking to predict the he alth of siblings of a sick child;
- pregnant women with an increased risk of having a child with abnormal he alth.
2. Prenatal diagnosis is called prenatal determinationcongenital or hereditary pathology of the fetus. In general, all pregnant women should be examined to exclude hereditary pathology. For this, ultrasound examination, biochemical studies of the serum of pregnant women are used. Indications for prenatal diagnosis can be:
- presence in the family of an accurately diagnosed hereditary disease;
- mother's age over 35;
- Women's previous spontaneous abortions, stillbirths of unknown cause.
The importance of prevention
Medical genetics is improving every year and gives more and more opportunities to prevent most hereditary diseases. Each family with he alth problems is given full information about what they are at risk and what they can expect. By raising the genetic and biological awareness of the broad masses of the population, promoting a he althy lifestyle at all stages of human life, we increase the chances of humanity to give birth to he althy offspring.
But at the same time, polluted water, air, food products with mutagenic and carcinogenic substances increase the prevalence of multifactorial diseases. If the achievements of genetics are applied in practical medicine, then the number of children born with hereditary genetic diseases will decrease, early diagnosis and adequate treatment of patients will be available.
