Gene diseases are groups of diseases that are heterogeneous in clinical manifestations and arise under the influence of mutations at the gene level. Separately, one should consider 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.
What are multifactorial hereditary diseases?
Specifically, this group of diseases has one clear difference from gene diseases. Multifactorial diseases begin to appear with adverse environmental factors . Some scholars have suggested that a genetic predisposition may never occur if environmental factors do not occur.
The etiology and genetics of multifactorial diseases is very complex, the origin has a multi-stage structure and can be different in the case of each specific disease.
Varieties of multifactorial pathologies
Conditionally multifactorial hereditary diseases can be divided into:
- native malformations;
- mental and nervous illnesses;
- age-related diseases.
Depending on the number of genes involved in the pathology, there are:
- Monogenic diseases - have one mutant gene, which creates a person’s predisposition to a particular disease. In order for the disease to begin to develop in this case, it will be necessary to influence one specific environmental factor. This may be a physical, chemical, biological or drug exposure. If a specific factor has not arisen, even if there is a mutant gene, 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 also not occur.
- Polygenic hereditary diseases or multifactorial diseases are determined by pathologies in many genes. The action of multifactorial signs may be discontinuous or continuous. But any of the diseases can occur only with the interaction of many pathogenic genes and environmental factors. Normal human characteristics, such as intelligence, height, weight, skin coloration, are continuous multifactorial signs. Isolated congenital malformations (cleft lip and palate), congenital heart disease, neural tube defects, 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 symptoms.
Diagnosis of MPD
Various 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 in relatives occur 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.
MPF-specific criteria
- The degree of kinship 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 the patient's relatives.
- The severity of the disease of the affected relative affects the genetic prognosis.
Multifactorial diseases
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 labored breathing or suffocation.
- Peptic ulcer disease, which is a chronic recurrent disease. It is characterized by the formation of ulcers in the stomach and duodenum due to a violation in the general and local mechanisms of the nervous and humoral systems.
- Diabetes mellitus, in the process of which both internal and external factors causing disturbances in carbohydrate metabolism are involved. The occurrence of the disease is strongly influenced by stress factors, infections, injuries, operations. Risk factors can be viral infections, toxic substances, overweight, atherosclerosis, decreased physical activity.
- Coronary heart disease is a consequence of a reduced or complete lack of myocardial blood supply. 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 prophylaxis is aimed at terminating the pregnancy if the fetus has a high probability of illness or if the diagnosis is already made prenatally. The basis for 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 normocopy. What it is? This is the development of a healthy child with a pathogenic genotype. Normocopy with the appropriate treatment 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. Genetic counseling is specialized medical care. Today, one of the main types of prevention of hereditary and genetic diseases. For genetic consultation consult:
- healthy parents who have given birth to a sick child, where one of the spouses has a disease;
- families with practically healthy children, but who have relatives with hereditary diseases;
- parents seeking to make a prognosis for the health of the brothers or sisters of a sick child;
- pregnant women who are at increased risk of having a baby with abnormal health.
2. Prenatal diagnosis is called the antenatal determination of the congenital or hereditary pathology of the fetus. In general, all pregnant women should undergo examination to exclude hereditary pathology. For this, an ultrasound examination, biochemical studies of the serum of pregnant women is used. Indications for prenatal diagnosis may include:
- the presence in the family of a precisely diagnosed hereditary disease;
- mother's age in excess of 35 years;
- previous spontaneous abortions in women, stillbirths with unclear causes.
The importance of prevention
Medical genetics is improved every year and provides more and more opportunities to prevent the majority of hereditary diseases. Each family with health problems is given full information about what they risk and what they can count on. By increasing the genetic and biological awareness of the broad masses of the population, promoting a healthy image at all stages of human life, we increase the chances of humanity to have healthy 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.