Multifactorial diseases, their genetics and prevalence

Genetic diseases are groups of diseases that are heterogeneous in terms of clinical manifestations, caused by mutations at the gene level. Separately, we should consider a group of hereditary gene diseases that arise and develop against a background of a defect in the hereditary apparatus of cells and the influence of unfavorable factors of the surrounding world.

What are multifactorial inherited diseases?

Specifically, this group of diseases has one distinct difference from gene diseases. Multifactorial diseases begin to appear with unfavorable factors of the external environment. Some scientists suggest that the genetic predisposition may not manifest itself unless the surrounding factors arise.

The etiology and genetics of multifactorial diseases is very complex, the origin has a multistage 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 defects of development;
• Mental and nervous illness;
• Age-related diseases.

Depending on the number of genes involved in pathology, distinguish:

• Monogenic diseases - have one mutant gene, which creates a predisposition of a person to a particular disease. In order for the disease to develop in this case, it will be necessary to influence one specific environmental factor. This can be a physical, chemical, biological or medicinal effect. If a specific factor does not arise, even if the mutant gene is there, the disease will not develop. If a person does not have a pathogenic gene, but is exposed to an external environmental factor, the disease also does not arise.
• Polygenic hereditary diseases or multifactorial diseases are determined by pathologies in many genes. The action of multifactorial features can be discontinuous or continuous. But any of the diseases can arise only through the interaction of many pathogenic genes and environmental factors. Normal human characteristics, such as intelligence, height, weight, skin color, are continuous multifactor features. Isolated congenital malformations (cleft lip and palate), congenital heart disease, neural tube defects, polistorenosis, hypertension, peptic ulcer and some others have a higher frequency of occurrence in close relatives than in the general population. Multifactorial diseases, the examples of which are mentioned above, are "intermittent" multifactorial signs.

Diagnostics of MFZ

Various types of research help to 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 doctors' practice, that is, when repeated cases of malignant diseases occur in one family tree among relatives.

Doctors often resort to studying twins. This method, like no other, allows us to operate with reliable data on the hereditary nature of the disease.

Studying multifactorial diseases, scientists pay much attention to the study of the links between the disease and the genetic system, as well as the analysis of the genealogy.

Characteristic criteria for MFZ

• 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 the genetic plan), the greater the likelihood of the disease.
• The number of patients in the family affects the risk of disease in the relatives of the patient.
• The severity of the illness of the affected relative affects the genetic prognosis.

Diseases related to 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 bouts 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 a violation in the general and local mechanisms of the nervous and humoral system.

- Diabetes mellitus, in the process of occurrence of which both internal and external factors that cause disorders of carbohydrate metabolism are involved. The occurrence of the disease is strongly influenced by stressors, infections, injuries, surgeries. Risk factors may include viral infections, toxic substances, overweight, atherosclerosis, and reduced physical activity.

- Ischemic heart disease - is the result of a reduced or total lack of supply of blood to the myocardium. This is due to pathological processes in the coronary vessels.

Prevention of multifactorial diseases

The types of preventive measures preventing the emergence 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. It can be realized in the planning of procreation and improvement of the human environment.

Secondary prophylaxis is aimed at aborting the pregnancy if the probability of the disease in the fetus is high or the diagnosis is already established prenatally. The basis for such a decision can be hereditary disease. Occurs only with the consent of a woman on time.

Tertiary type of prophylaxis 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 development of a healthy child with a pathogenic genotype. Normokopirovanie with the appropriate treatment complex can be done in utero or after birth.

Prevention and its organizational forms

Prophylaxis of hereditary diseases is realized in the following organizational forms:

1. Medical genetic counseling is specialized medical care. Today, one of the main types of prevention of hereditary and genetic diseases. Medical and genetic counseling is addressed by:

• Healthy parents who gave 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 who want to make a prognosis for the health of the brothers or sisters of a sick child;
• Pregnant women with an increased risk of having a child with abnormal health.

2. Prenatal diagnosis is the prenatal determination of congenital or hereditary pathology of the fetus. In general, all pregnant women should be examined 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:

• Presence in the family of an accurately diagnosed hereditary disease;
• The mother's age exceeding 35 years;
• Previous spontaneous abortions in women, stillbirths with unclear reasons.

Importance of prevention

Medical genetics is improved every year and gives more and more opportunities to prevent the majority of hereditary diseases. Every family with health problems gives full information about what they are risking and what they can count on. By increasing the genetic and biological awareness of the general public, by promoting a healthy image in all life stages of a person, we increase the chances of mankind to have a healthy offspring.

But at the same time, contaminated 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 be reduced, early diagnostics and adequate treatment of patients will be available.