Sickle cell anemia dominant gene or. How sickle cell anemia beats malaria

Sickle cell anemia is a disease that is hereditary. With it, abnormal hemoglobin appears and the shape and size of red blood cells are modified.

Sickle cell anemia: causes

For the main cause of this type of anemia, it is customary to take a mutation in the genes, as a result of which the production of abnormal hemoglobin begins. After the loss of an oxygen atom, which hemoglobin attaches, its structure resembles a high-polymer gel. Its solubility is violated, to be more precise, it decreases by about a hundred times.

Sickle cell anemia is inherited in an autosomal receptive pattern. Since the defect is inherited from one of their parents, both normal hemoglobin and red blood cells are often present in the blood. The disease usually begins its development early and its course is quite severe. In this case, sickle cell anemia is inherited as an incompletely dominant gene.

If both parents suffered from such a disease (which, in principle, is quite rare), then only sickle-shaped red blood cells will be in the blood of the unborn child.

Sickle cell anemia and mutation are two concepts that are inextricably linked. The sickle cell anemia gene is something that can make a person's life much more difficult.

Sickle cell anemia: signs

Homozygous anemia of this variety is usually detected in children by four to five months of age, and we are talking about detection through observation of symptoms that begin to manifest themselves. The percentage of free crescent-shaped red blood cells by this time is ninety percent. Such children apparently lag behind in physical and mental development, they show manifestations of hemolytic anemia. The normal formation of the skeleton is disturbed: the skull becomes tower-shaped, the frontal cranial sutures take the form of a crest.

The entire period of development of sickle cell anemia can be divided into three periods:

From six months until the child reaches two or three years;
From three to ten years;
Development after the child reaches the age of ten.

The first signs indicating sickle anemia can be considered symmetrical swelling of the limbs, yellowing of the skin, pain in the chest, back and abdomen. Sometimes there is splenomegaly. Children with this diagnosis are more susceptible to infections than other children. Symptoms will be all the more pronounced, the higher the concentration of abnormal hemoglobin in red blood cells.

If the patient is exposed to certain external factors, he may periodically experience sickle cell crises. Under these factors, it is customary to understand pregnancy, hypoxia, constant stress and dehydration of the body.

How does a hemolytic crisis manifest itself?

The skin becomes either more yellow than usual, or vice versa begins to turn pale;
Gait becomes febrile;
If a blood test is taken during this period, a large amount of indirect bilirubin will be recorded in it;
Hemoglobin, of course, will be reduced compared to the norm.

Heterozygous carriers of the gene for this type of anemia, that is, those to whom the disease was transmitted from one of the parents, under normal conditions, feel like people are quite healthy. Anemia in them and morphological modifications of erythrocytes occur only when they are subjected to severe oxygen starvation, for example, when flying in an airplane, mountain climbing and intense physical exertion. Such a crisis can sometimes lead to death.

Human sickle cell anemia: complications

If the disease enters the stage of chronicity and against the background of its course, the patient encounters periodic crises, this can lead to irreversible changes in the body and even death of the patient. In a third of patients, the spleen decreases in size due to the replacement of functional scar tissue. Sepsis, pneumonia and meningitis can easily occur.

Vascular occlusive crises can lead to impotence, ischemic stroke in children, and renal failure. In women with this diagnosis, the menstrual cycle is established later, there is a tendency to preterm labor and the likelihood of miscarriage increases if the woman manages to become pregnant. Long-term hemolysis, in which an excessive amount of bilirubin is formed, leads to cholelithiasis and cholecystitis. Also, patients with this disease tend to suffer from leg ulcers and osteomyelitis.

Sickle anemia in humans: diagnosis

How can this disease be detected in a patient? This diagnosis can only be made by a hematologist, based on observations of the patient, his complaints and hematological changes in the blood test. Sometimes it is necessary to study the family-hereditary factor.

The fact of the transmission of the disease to the child from the mother can be detected even during the period of bearing the child by amniocentesis or biopsy of the chorionic villi.

A blood smear at diagnosis usually shows sickle-shaped red blood cells. Hemoglobin electrophoresis allows you to determine the form of the course of hereditary hemolytic anemia, which can be either homozygous or heterozygous. Differential diagnosis is designed to exclude the occurrence of other types of anemia, bone and joint tuberculosis, osteomyelitis, rickets and A-type hepatitis.

Sickle cell anemia in humans: treatment

Unfortunately, this disease is usually differentiated as an incurable blood disease. It is vital for patients who suffer from it to be constantly monitored by a hematologist, to take measures that are aimed at preventing sickle cell crises. If such crises do occur, symptomatic treatment will be required.

In a crisis, the patient must be hospitalized. In order to relieve such an acute condition, oxygen therapy, the introduction of antibiotics and painkillers are used. If the course is too severe, it will be necessary to transfuse the mass of red blood cells.

Sickle cell anemia is a severe hereditary disease that, in the absence of supportive therapy, threatens to cause deadly complications. The highest prevalence of pathology is observed on the African continent. It has been established that people suffering from this disease practically do not get malaria.

Features of the disease, its characteristics

Sickle cell anemia is a genetically determined hemoglobinopathy - an altered structure of hemoglobin. This protein is part of erythrocytes - blood cells that ensure the delivery of oxygen from the lungs to all tissues of the body and the removal of carbon dioxide from them.

In the blood of a healthy person, approximately 90% of hemoglobin of the Hb A type and up to 10% of Hb F are found. In sickle cell anemia, the first type of protein is replaced by the pathological type of Hb S.

The transformation of hemoglobin occurs when the oxygen content decreases, when red blood cells reach tissues distant from the lungs. Polymerizing and acquiring a crystalline structure, hemoglobin chains give blood cells rigidity and an elongated crescent shape. At the first stages of the development of the disease, this process is reversible - reaching the lungs, erythrocytes add oxygen and their normal form is restored.

But gradually, with each subsequent cycle of blood circulation, the permeability of the cell membrane increases, the loss of water and potassium ions increases. In this regard, the plasticity of erythrocytes decreases, and the ability to restore the normal shape is lost. They can no longer easily pass through the narrow lumen of the capillaries, because of this there is a risk of blockage of the vessels. Hemoglobin, which is part of crescent-shaped erythrocytes, is able to bind a smaller amount of oxygen, therefore, oxygen starvation of tissues increases.

Due to the fragility of the membrane, pathologically altered red blood cells are rapidly destroyed. In the absence of timely assistance, all these phenomena can lead to serious complications and death.

The peculiarity of the disease is that it is inherited according to the principle of incomplete gene dominance. With a slight concentration in the blood of a pathological variety of hemoglobin, patients may feel less pronounced hypoxia, in some cases it manifests itself only with increased physical exertion. If the majority of red blood cells are of type A, the symptoms of the disease will be most pronounced, and the course will be severe.

You can learn more about the disease and clearly see its essence by watching this video:

Causes of the disease

Sickle cell anemia occurs when the gene responsible for the formation of the b-globin chain is damaged by a mutation. The disease is characterized by an autosomal recessive type of inheritance, therefore, for its development, it is necessary that the genetic material that has undergone changes be transferred to the child from both parents. However, they can be healthy and be carriers of the mutant gene (the risk of developing the disease in their children is 25%). This form of the disease is called homozygous.

When a child inherits a damaged gene from only one of the parents, a heterozygous form of sickle cell anemia develops. In this case, the number of red blood cells with a pathological type of hemoglobin is balanced by normally functioning blood cells and the person is an asymptomatic carrier without clinical manifestations of pathology. The risk of getting a gene of predisposition to this type of anemia for children, one of whose parents is a carrier, reaches 50%.

Medicine does not yet have information about the exact causes of the appearance of mutations due to which sickle cell anemia occurs. As scientific studies show, the following factors can contribute to damage to various parts of DNA and the development of hereditary diseases:

Malaria disease. It is assumed that when its pathogens, plasmodium, enter the body, a mutation may occur as a protective reaction that prevents the infection from penetrating into erythrocytes.
The influence of viruses - the composition of viral nucleoproteins includes RNA or DNA. Getting into the genetic apparatus of human cells, they force it to produce new viral units. This process can also be accompanied by chromosome mutations.
Ionizing radiation obtained with an increased radiation background of the environment, frequent x-ray examinations.
Contact with harmful chemicals, in particular with epichlorohydrin used in pharmacological production, styrene used for the manufacture of synthetic polymers, inhalation of tobacco smoke, ingestion of heavy metal salts. These substances are capable of causing mutations, including those that contribute to the malignant transformation of tissues.
Drugs that affect chromosomes. The highest mutagenic activity is possessed by cytostatics used to suppress the growth of tumors, immunosuppressants and agents containing mercury used to suppress pathologically functioning immune cells.

Symptoms of sickle cell anemia, the course of the disease

In the heterozygous form of the disease, clinical signs may be absent for a long period of time, appearing with the development of conditions leading to oxygen starvation of the body. It can be intense physical activity, loss of a large volume of blood, being at a considerable height above sea level. The homozygous form of the disease manifests itself more severely, can lead to disability or death of a person. During the course of the disease, three stages are distinguished: the first (initial), second and third.

Signs of the initial stage of the disease

The first stage is manifested at the age of 5 months by swelling and soreness of tissues in the joints, hands, legs and feet due to blockage of capillaries.

The formation of many sickle-shaped erythrocytes, followed by massive destruction in small vessels, the liver, bone marrow, and spleen, causes the development of hemolytic crises. These conditions may be interspersed with episodes of remission or go in a continuous series.

Hemolytic crises are characterized by fever, a feeling of chills, shortness of breath, dizziness, and the acquisition of an icteric hue by the skin. Jaundice is explained by the high concentration of bilirubin in the blood - the liver does not have time to neutralize this substance, which is released in large quantities during the numerous death of red blood cells. In children, pallor and dry skin are noted, the color of urine darkens, they lag behind in development (physical, including delayed puberty, and mental). Thrombosis of capillaries can subsequently lead to the development of aseptic necrosis of the femoral head.

Clinical manifestations of the second stage of sickle cell anemia

Active death of sickle-shaped erythrocytes causes a rapid progression of hemolytic anemia. In the bone marrow, seeking to compensate for the deficiency of red blood cells, there is an intensive formation of these cells. This leads to its hyperplasia. Visually, an increase in the volume of the bone marrow is manifested in a change in the structure of the bones of the skeleton - elongation of the arms, legs, skull, curvature of the spine, the appearance of bulges in the forehead and crown. The child is less physically developed than his peers, his weight is reduced, puberty comes late.

The patient has an enlarged spleen and liver, due to vascular thrombosis there is a risk of developing a cerebral stroke, the formation of trophic ulcers on the skin of the extremities, head, torso. Hemosiderosis is noted - a high density of iron in blood cells and tissues of internal organs, which threatens the development of cirrhosis of the liver, heart failure and other dangerous pathologies.

Features of the third stage of the disease

The transition of the disease to the third stage occurs on average 5 years after the onset of the first symptoms of sickle cell anemia. There is a danger of joining infectious complications, including sepsis. The patient may be disturbed by severe pain in the tissues of the body that do not receive the required amount of oxygen due to blockage of blood vessels. Strengthening of the pain syndrome can cause the action of low temperatures, overwork, stress, infection.

Diagnosis of the disease, examinations, tests

To make a final diagnosis, hematologists, in addition to the data obtained during examination and questioning of patients and their relatives, study the results of blood tests (general and biochemical), hemoglobin electrophoresis, ultrasound, X-ray examination. Blood taken from patients is placed in a hematological analyzer to determine the quantitative composition of erythrocytes, leukocytes, platelets, reticulocytes, total hemoglobin, ESR, hematocrit values (percentage of the number of cell elements to plasma).

Conducting a biochemical analysis shows the level of bilirubin, free iron, liver enzymes ALT and AST, plasma levels of haptoglobin and free hemoglobin. Hemoglobin electrophoresis allows you to determine the presence in the blood of various types of hemoglobin (A, A2, F, S). Ultrasound examination helps to detect enlargement of the spleen and liver, deterioration of blood supply to organs and limbs, hemorrhages caused by vascular thrombosis. The X-ray method determines the distortion of the shape of the vertebrae, the deformation of the bone tissue (the bones are narrow and long), its damage to osteomyelitis (purulent inflammation of an infectious nature).

Treatment options for sickle cell anemia

Currently, no drugs or treatments have been developed that would completely cure the disease. Medical care is provided to patients during periods of exacerbations, therapeutic measures are aimed at eliminating the symptoms of hemolytic crises, alleviating the patient's condition, prolonging his life and improving its quality. The relief of attacks of the disease includes strict adherence to bed rest.

To eliminate hemolytic crises, the following methods of treatment are used:

To increase the level of hemoglobin and the content of erythrocytes allows the transfusion of blood and erythrocyte mass.
Oxygen therapy helps to prevent the formation of sickle-shaped erythrocytes and the negative consequences caused by their rapid destruction. When using an oxygen mask, about 5 liters of oxygen per minute are supplied to the patient's lungs.
To eliminate the pain syndrome, potent painkillers are used, in particular, narcotic drugs: Promedol, Tramadol, Morphine.
To increase the concentration of hemoglobin Hb F in erythrocytes, which does not undergo transformation into a variety of Hb S, the medication Hydrea is prescribed. It is used when patients reach adulthood in the event of at least 3 exacerbations of the disease throughout the year.
To reduce the excess iron content in the body allows the appointment of drugs Desferal and Exjade.
To prevent the development of a crisis, intravenous infusion of rehydration solutions helps.
To prevent the addition of an infection and the development of complications caused by it, newborns suffering from sickle cell anemia, starting from the age of 2 months, are given antibiotic therapy. Its duration can be 5 or more years. To increase the body's resistance to pneumococci, the child is given a specific vaccination.
If indicated, removal of the spleen is performed. The operation improves the patient's condition for a long period of time.
A bone marrow transplant has a fairly high efficiency. The disadvantages of this method are significant cost, the need to select a compatible donor and then take drugs that depress the immune system to prevent rejection of donor tissue.

Prognosis, possible complications

To prevent the development of severe complications, it is necessary to identify the presence of sickle cell anemia as early as possible in the development of the disease. In the first years of a child's life, a sharp deterioration can occur as a result of infection of the body. In these cases, urgent hospitalization of the patient is necessary. The average life expectancy of patients is 50 years.

Regular therapeutic measures can reduce the frequency of exacerbations of the disease, improve the well-being of patients and reach old age.

Complications of the disease are caused by thrombosis of small vessels and the resulting violation of the blood supply to the internal organs and parts of the body. They manifest themselves in the form of ulcerations on the skin and the development of infectious diseases when pathogenic microorganisms enter the body through the affected areas. When the arteries supplying blood to the retina are blocked, retinal detachment, partial or complete loss of vision can occur.

The overlap of the sinusoids of the spleen leads to its increase and the occurrence of hypersplenism, in which, due to stagnation of blood, accelerated destruction of not only pathological, but also normal blood elements occurs. Thrombosis of coronary vessels threatens the development of myocardial infarction. Damage to the veins of the kidneys causes kidney failure.

The blockage of blood vessels of the male genital organ by crescent-shaped red blood cells leads to the appearance of priapism (prolonged, painful erection), and in some cases to impotence. With blockage of arteries in various parts of the spinal cord and brain, there is a violation or loss of motor functions, in severe cases - ischemic stroke. These conditions can cause serious damage to the health of the patient, especially in early childhood, and some of them even lead to death.

Disease prevention

Due to the fact that the genetic predisposition to sickle cell anemia is passed from parents to children, it is appropriate to warn married couples before marriage about such a risk. Appropriate blood tests will help identify the pathological gene.

A number of preventive measures can reduce the likelihood of hemolytic crises and complications in patients:

The place of residence of the patient should be above sea level no higher than at an altitude of 1500 m.
Air travel should be avoided to prevent rarefied atmospheric air and pressure drops from entering the area, leading to a decrease in the supply of oxygen to the tissues of the body.
It is desirable that mild climatic conditions prevail in the patient's area of residence without excessively high or low temperature values.
It is necessary to exclude smoking and the use of alcoholic beverages.
Regular intake of folic acid allows you to increase the formation of red blood cells.
To prevent dehydration, you should drink at least 1.5 liters of water or other liquids throughout the day.
Stress and physical exertion should be avoided, light work should be chosen that is not associated with being in rooms with high or low air temperatures.

Sickle cell anemia is a disease that is not treated, but with timely diagnosis it is successfully stopped. Patients need to visit the medical facility regularly for medical examinations and to detect changes in their health status. Compliance with preventive measures will significantly reduce the risk of crises.

Compared to other blood diseases, sickle cell anemia is rare and is diagnosed in people in the Middle East and Africa.

The indigenous population of these areas is a carrier of hemoglobin of an abnormal structure. But it is interesting that this feature allows him to protect himself from the penetration of the causative agent of malaria into the body.

Information about the disease

The disease refers to the varieties of pathology. Its name is due to the fact that the shape of red blood cells is irregular, resembling a sickle. Due to a defect in their structure, the functions of the blood and its composition change.

Red blood cells cannot be fully saturated with oxygen, and their life cycle is reduced. They are destroyed not after three or four months (according to the norm), but much earlier.

The same thing happens with hemoglobin inside sickle cells. Hence the development of anemia, since the bone marrow does not have time to produce new blood cells.

Causes of blood disease

Sickle cell anemia is classified as a hereditary disease. As a result of a gene mutation, hemoglobin S is synthesized, the structure of which is changed compared to normal.

Glutamic acid in the peptide chain is replaced by valine, and hemoglobin becomes a poorly soluble gel of a high polymer type. Therefore, the erythrocytes that carry this form of hemoglobin take the form of a sickle. Their inability to plasticity contribute to the blockage of small vessels by red cells.

The type of inheritance of the disease is recessive. If a gene is passed on to a child from one of the parents who carries the mutation, then the child will have normal cells along with the altered cells in the blood. In carriers of the gene with heterozygous anemia, the symptoms of pathology often manifest themselves in a mild form.

When a defect is inherited from both mother and father, the disease takes on severe forms and is diagnosed in young children. It is called homozygous.

A provocateur of a gene mutation in a person is determined by:

the causative agent of malaria;
viruses that multiply inside cells;
ionizing radiation that affects the human body for a long time;
heavy metal compounds related to aggressive mutagens;
components of medicines containing mercury.

As a result of these factors, erythrocytes are produced sickle-shaped.

Difference between dominant and recessive inheritance

Any genetic disease is inherited in two types. Dominant is characterized by the fact that the disease will be transmitted to a representative of each generation, regardless of gender.

Even if one of the parents is the carrier of the gene, then 25 percent of the offspring will suffer from pathology.

The recessive type of inheritance is characterized by the fact that the gene mutation is found in only half of the offspring with one carrier. If the disease gene is carried by one of the parents, then the symptoms may appear after a generation.

Genetics claims that recessive inheritance occurs more often in men. Girls can inherit it from their father. From healthy parents, a son with a recessive gene is possible.

What causes anemia

There may be a pathology of the blood for other reasons. This includes the presence in adults:

lupus erythematosus;
blood diseases;
diseases of the immune system - amyloidosis;
sepsis;
chronic glomerulonephritis;
bacterial endocarditis.

Symptoms of sickle anemia may appear as a result of a blood transfusion, after an organ transplant or prosthetics.

These causes are less common than the hereditary factor of the disease.

Clinical picture and stages of the disease

Depending on the number of defective red blood cells in a person's blood, the following symptoms of the disease occur:

Thrombosis of blood vessels leads to swelling and soreness of the joints, bone tissues.
In the absence of nutrition and lack of oxygen, osteomyelitis develops. With the development of the disease, the limbs become thinner, the column of the spine is bent.
At the second stage of the disease, anemia develops with the gradual destruction of red blood cells - hemolysis. In this case, the patient has an increase in the liver or spleen. Biochemistry reflects what is happening. With the maximum development of the destruction of red blood cells, the body temperature rises.
Change in color of urine to red-brown or black. Yellowness of the skin, mucous membranes is detected.

These signs appear in heterozygous heirs who are carriers of the gene, but only during periods of intense physical exertion, flights on air liners, and climbing high into the mountains. Hypoxia of the brain at this moment provokes the onset of a hemolytic crisis.

How the disease progresses in children

Both parents, as carriers of the gene, pass the disease of the homozygous type to their child. In the blood of a newborn, by the age of four to five months, 90 percent of the sickle-shaped form of erythrocytes predominates. Anemia develops against the background of hemolysis, the rapid breakdown of red cells. In children:

growth retardation develops, mental abilities are reduced;
there are signs of curvature of the spine;
the frontal sutures of the skull thicken;
the cranium is deformed, acquiring the appearance of a tower;
swollen joints;
there is pain in the bones, muscles of the chest, abdomen;
yellowing of the skin and sclera.

Symptoms are more pronounced if the concentration of defective hemoglobin increases.

The addition of infection, hypoxia, stress, dehydration in the hereditary form of anemia leads to the development of crises, and the rapid breakdown of red blood cells leads to increased production of bilirubin and coma.

Diagnostic methods

By external manifestations, it is not always possible to make a correct diagnosis. Therefore, they carry out:

General blood analysis. It will show an accurate picture of the peripheral blood, inform about the state of the internal organs.
Blood biochemistry to assess the qualitative composition of this biological fluid. With anemia, the level of bilirubin will be higher than normal, and the content of free hemoglobin and iron will also be increased.
Electrophoresis. The procedure will show what type of hemoglobin the patient has.
Ultrasonography. It will help to identify an increase in the liver, spleen, the presence of heart attacks in them. Diagnostics will also show a violation of blood flow in the limbs.
A puncture taken from the bone marrow will reveal an expansion of the erythroblastic germ that produces blood cells.
X-ray of the spine, the entire human skeleton. The picture will show deformations of bones, vertebrae, purulent processes in them.

In heterozygotes, only tests can confirm the presence of the disease gene. This will warn carriers of the mutation against rash acts in terms of health, and will help them competently plan the birth of children.

blood picture

In patients with sickle cell anemia, the presence of:

decrease in hemoglobin level to 50-80 grams per liter;
cells with Jolly bodies, Kabo rings;
an increased number of immature erythrocytes - reticulocytes;
normochromia;
high levels of leukocytes.

And in this type of anemia, the bone marrow produces immature red blood cells, releasing them into the peripheral blood.

Conservative therapy of the disease

The causes and clinic of sickle cell anemia are such that it cannot be completely eliminated, but the risk of undesirable consequences can be reduced. The complex of measures for treatment includes transfusion of donor blood.

Thanks to this procedure, oxygen will be transported through the patient's body for some time. Indications for transfusion are life-threatening conditions, when the level of hemoglobin is sharply reduced. But the disadvantage of the procedure is a lot of adverse reactions of the body..

From medicines use:

to eliminate the pain syndrome - the synthetic drug Tramadol;
drug with analgesic, anti-shock effect - Promedol;
excess iron in the blood is eliminated by Desferal or Exjade;
glucocorticosteroids to normalize the size of the liver, spleen;
to prevent the attachment of a bacterial infection - Amoxicillin, to eliminate it - Cefuroxime, Erythromycin.

The treatment must include drugs that contain folic acid.

One of the effective methods of stopping an acute condition in anemia is oxygen therapy, or hyperbaric oxygenation. Under the influence of gas entering the human body under pressure, oxidative processes return to normal, and the level of intoxication decreases.

For a while, a splenectomy, an operation to remove the spleen, helps to improve the patient's condition.

Given the pathogenesis of anemia, hematologists can only take measures to prevent crises, relieve the patient of pain and other symptoms of the disease. Completely get rid of the disease will not work.

Possible Complications

The long course of sickle anemia is fraught with often recurring crises, which causes a complication of a serious condition in patients:

Changes in the spleen occur due to the processes of replacement of organ tissues with connective tissue. In this case, there is a decrease in the size of the spleen, its wrinkling.
There are violations in the form of renal failure, inflammation of the lungs and meninges, sepsis.
The consequence of the disease in women is a tendency to miscarriages.
Lack of nutrition of the heart muscle leads to myocardial ischemia.
It does not do without the development of cholecystitis, the formation of stones in the gallbladder, which is a consequence of the toxic effect of bilirubin in the blood.

Complications in homozygous anemia cannot be avoided. Only constant monitoring of the state of the blood, bringing it back to normal will alleviate the suffering of the patient.

Prevention measures

The prognosis for patients with sickle anemia is not always good. If children get the homozygous form of the disease, they die from infections or from blockage of blood vessels.

For carriers of the defective gene, the prognosis is more reassuring, but they must follow a number of rules, which include:

choosing a place of residence where the climate is temperate and the altitude is within 1.5 thousand meters;
exclusion of alcohol and drugs;
to give up smoking;
choosing a profession that is not associated with heavy loads, contact with toxic substances and work in rooms with high air temperature;
drinking a large amount of fluid daily, at least one and a half liters.

Before the birth of a child, both parents are examined. A hereditary disease can be detected if, after the study of the gene material, a mutant of sickle cell anemia is detected.

The determination of the mutagen at the early stages of embryo development is carried out using modern methods.

A positive result of the study poses a problem for future parents. After all, only they can appreciate the importance of the decision to terminate the pregnancy in a timely manner or hope for the birth of a healthy child, a carrier of the gene without symptoms of anemia.

One of the most common tests prescribed by different doctors and for various diseases is a complete blood count. Each person rents it dozens of times in his life. A blood test is very informative: blood circulates throughout the body and contains information about all the processes that occur in it.

Blood conveys this information with the help of various indicators, for each of which medicine has long established its own limits of the norm. But blood is not only an informant: it is a kind of liquid organ, which means that, like all organs, it is susceptible to diseases.

A group of such diseases in humans are anemias of various origins, and almost all of them respond quite well to treatment. However, there are anemias that a person cannot prevent or cure. One such serious disease is sickle cell anemia.

sickle anemia and red blood cells

Red blood cells, as many people know, are red blood cells filled with hemoglobin. There are many erythrocytes, they make up about a quarter of all cells in the body, and they are all deliverers.

The transport task of red blood cells consists of two components: the transport of oxygen from the lungs throughout the body and the transport of carbon dioxide from organs to the lungs. Thus, the respiration of the body is ensured.

Erythrocytes are round in shape and have high plasticity, and therefore they can pass through much smaller capillaries without any difficulties. However, with sickle cell anemia, thought out by nature, the round shape of red blood cells changes to a narrow crescent, which gave the name to the disease.

Altered erythrocytes are unable to cope with their work qualitatively. The oxygen delivered by them is not enough to provide the necessary level of oxygen in the cells of the body. In addition, erythrocytes in anemia are catastrophically small, since their life expectancy is an order of magnitude less than that of normal ones. And they get stuck in the capillaries, disrupting the blood supply to the tissues and organs.

Types and causes of the disease

Sickle cell anemia is a disease that is inherited, and nothing else. If a man and a woman planning a child are the owners of this disease, then the child can take on a defective gene from each of them.

Two defective genes is a clear form of disease, often with severe symptoms and sometimes leading to disability and even death.

But another option is also possible: if the child takes the mutated gene from only one of the parents, and the second one has a normal one. In this case, the disease will be asymptomatic. This is the so-called carriage, which may not affect the quality of life of the child.

It should only be taken into account that the absence of symptoms will not make the defective gene more normal. And if two carriers of such a gene decide to have a child, they may well get the first option, with a vivid clinical picture.

The probability of having a healthy child is, in general, equal to zero if at least one of the parents suffers from an open form of the disease. In this case, the most favorable outcome that can be hoped for is the birth of a child with a carrier. However, even this option is excluded if both parents have the disease in an open form - the child will share their fate.

If both parents are carriers of an asymptomatic form of the disease, then they have a chance to give birth to a healthy child who will not be affected by their disease at all: the probability of this is 25%.

However, it so happened that the erythrocytes, which acquired a crescent shape during the disease, did not like the malarial plasmodium. This can hardly be called a coincidence. There is even a version that the gene mutation that causes sickle cell anemia is protection against malaria.

Of course, in the modern free world, where a person has ceased to be tied to the place of his birth, this disease can be found in almost any corner of the Earth.

Symptoms of anemia

The development of sickle cell anemia can be divided into three periods:

infancy and early childhood;
childhood;
adolescence and older.

The first stage of anemia appears from 3-4 months, until this time the child is no different from other babies. Symptoms of the first period of anemia are swelling and soreness of the extremities as a result of circulatory disorders. This can eventually lead to the fact that the child does not want to learn to walk: the pain and inconvenience of walking will be strong repulsive factors.

Another symptom of anemia is the condition of the skin: its lethargy and pallor, as well as the presence of a yellowish tint. This also applies to the mucous membranes: they do not have a characteristic pink color, but they can have a yellow tint.

The second stage - childhood - reveals even more symptoms (in addition to those already available):

lack of activity characteristic of childhood. Due to the lack of oxygen, the body becomes incapable of active actions, they cause rapid fatigue and begin to be perceived as undesirable;
dizziness - caused by the same lack of oxygen;
enlargement of the spleen, which makes the body weak before infections;
lagging behind in physical and mental development: all skills (speech, motor and cognitive) develop more slowly than those of their peers.

The last stage of anemia smoothly follows from the second: the developmental lag now captures the sexual sphere. Nevertheless, puberty in a child, albeit belatedly, occurs.

Other symptoms seen in adults with sickle cell anemia may include:

atrophy and death of tissues or organs;
skin diseases;
vision problems of varying severity (from reduced visual acuity to complete blindness);
heart problems of varying severity;
blood in the urine;
involuntary erection, which may be accompanied by painful sensations;
fragility and deformation of bones;
joint damage;
violation of sensitivity and motor functions of the limbs, up to their loss.

It is worth mentioning that each child may show different symptoms, but the entire list at once in one person is rather an exception, and rare.

In addition to all of the above, at any stage of anemia, hemolytic crises are possible, which are provoked by factors such as an infection, severe physical exertion, hypothermia, overheating, or rising to a high altitude (more than 2 km above sea level). Hemolytic crisis is expressed by:

lowering blood pressure;
vomiting;
weakness;
an increase in body temperature;
loss of consciousness.

Complications of sickle cell anemia

There are many complications of the disease, and all of them pose a threat to life.

In infants and toddlers, infection is a serious complication of sickle cell anemia. Serious because it can result in blood poisoning.

It is necessary to exercise extreme vigilance, and at the slightest suspicion of an infection in a child (loss of appetite, fever and capriciousness), immediately seek medical help.

If you sound the alarm on time, and start treatment of anemia with antibiotics in a timely manner, then the threat to the life of the child can be averted. Approximately after the child reaches 5 years of age, the risk of death is significantly reduced (but, alas, does not disappear).

In adults, as a result of prolonged blockage of the capillaries of the lungs or kidneys, pulmonary or renal failure may develop. This can lead to early death.

Blockage of capillaries can also occur in the lungs, which can lead to distress syndrome, which also often ends in death.

Another complication of sickle cell anemia is stroke. Also deadly. It is not a very common symptom of the disease, but it affects adults and children.

As for the ability to carry and give birth to a child, women with sickle cell anemia can do this. But they need constant monitoring by an experienced gynecologist, since the disease significantly increases the likelihood of miscarriage or premature birth.

In addition, an additional load falls on the woman's body, which can become that critical boundary, after which serious health problems will begin.

Diagnosis of the disease

Any blood disease is the sphere of a hematologist. Sickle cell anemia based on the examination and clinical picture, the doctor can only assume, but not accurately diagnose.

In order to obtain confirmation or refutation of the disease, tests are needed. Of course, first of all, these are blood tests: general and biochemical. By reading and comparing the results, the doctor will get a more accurate picture of what is happening.

Another important test for diagnosing anemia is hemoglobin electrophoresis. This is a laboratory method for the quantitative determination of normal and abnormal hemoglobins. Of course, with sickle cell anemia, the amount of normal hemoglobins will be greatly reduced, and abnormal, on the contrary, too high.

To confirm the diagnosis or clarify the harm caused by the disease to the body, ultrasound may be prescribed. It will show an enlarged spleen (if any) and circulatory disorders in the organs and limbs (again, if any).

Bones can also suffer from sickle cell anemia, becoming brittle, thinning, or deformed. X-rays will help identify these changes, so x-rays are also an important part of diagnosing anemia.

Treatment of sickle cell anemia

There is no way to get rid of this disease, so the treatment in general is to show as few symptoms as possible and to keep them as mild as possible. Here are some areas in which work can be done in the treatment of anemia:

exclusion of provoking factors (intense physical exertion, hypothermia, overheating, climbing to heights);
maintaining a healthy lifestyle (quitting smoking and alcohol, drinking plenty of water);
increasing the number of red blood cells with a blood transfusion;
increase in hemoglobin levels with the help of drugs;
the use of oxygen therapy;
taking painkillers;
taking drugs that reduce the level of iron in the blood;
prevention and treatment of infections.

How to prevent the disease?

Here the question can be put differently: how to prevent the birth of a child with sickle cell anemia. Not all parents at risk ask themselves this question: some will prefer to give birth to a child who will fight the disease all his life than to terminate the pregnancy.

However, there are also parents who choose the second option. To help them decide what to do next, research can determine at an early stage in the development of the fetus whether it has defective genes.

Around the eleventh week, you can perform a study of amniotic fluid, the accuracy of which is 99%. Another high-precision study is a chorionic villus biopsy (future placenta).

With these studies, sickle cell anemia will not come as a tragic surprise, allowing you to make an appropriate decision in time or mentally prepare for the upcoming one. And also to calm down and enjoy life, if it turns out that everything is in order with the genes of the child.

Sickle cell anemia is a disease that does not let you forget about yourself. It is worth letting it take its course - and it will begin to destroy the body until it achieves its death. Being attentive to your body is the main rule of people suffering from this disease. A rule that should ideally be observed by every person.

Despite the reduced life expectancy (on average, no more than 60 years), a person with sickle cell anemia may well live a happy life in the circle of loved ones, successfully repelling the attacks of the disease.

Sickle cell anemia is a disease of the hematopoietic system that is inherited. Pathology is characterized by a violation of the formation of hemoglobin chains in erythrocytes.

According to the ICD-10, sickle cell anemia has the code D57, and according to the ICD-9 it is assigned the code 282.6.

Sickle cell anemia - what is it?

Sickle cell anemia is considered to be the most complex form of blood disease, inherited. At the same time, instead of hemoglobin A, hemoglobin S is produced in the patient's body.

The mutated protein has an irregular structure, which gives it characteristics that it should not normally have. Red blood cells carrying hemoglobin S change their shape from a biconcave disc to the shape of a sickle, lengthening in size. Such erythrocytes are not particularly stable and are quickly destroyed in the vessels.

Most often, pathology occurs in Africa, both men and women are not equally affected. People with sickle cell anemia (both symptomatic and latent) are not susceptible to malaria.

Sickle cell anemia is caused by a mutation in the genes that is inherited. In this case, the HBB gene, which is responsible for the production of hemoglobin, suffers. As a result, in the body of a sick person, a protein is formed with the wrong position of the beta chain (glutamic acid in this chain is replaced by valine).

At the same time, hemoglobin continues to be produced, but its electrical properties are violated. If the body suffers from a lack of oxygen, then the protein changes its structure - it crystallizes and stretches into long chains, that is, it transforms into hemoglobin S (HbS). Erythrocytes react to such deformation by changing their shape. They also lengthen, which leads to thinning of their walls and destruction.

Sickle cell anemia is inherited in an autosomal recessive manner. In order for the pathology to make itself felt, the altered gene must be obtained from both the father and the mother. This is the so-called homozygous form, in which hemoglobin S molecules and no others will be present in the human blood.

If only one of the parents has a mutated gene, then the pathology will also be inherited, but the form of polymorphism will be heterozygous. At the same time, the child himself will not suffer from anemia, but will become an asymptomatic carrier of the pathological gene. In his blood, hemoglobin A and hemoglobin S will circulate in different proportions. If a person is healthy, then anemia does not manifest itself in any way, since hemoglobin A is enough to cover all the needs of the body. With severe dehydration or with anemia, it will make itself felt. A person who is an asymptomatic carrier of a mutated HBB gene can pass it on to their children.

The mechanism of development of sickle cell anemia

Erythrocytes in sickle cell anemia cease to perform their functions. Their walls become thin and brittle. In addition, the red blood cells that carry hemoglobin S are unable to transport the required amount of oxygen. They themselves cannot change shape and penetrate into the smallest capillaries.

All these pathological changes in the structure of erythrocytes and hemoglobin lead to the development of the following disorders:

The lifespan of erythrocytes is reduced. They quickly and massively die in the spleen.

Modified red blood cells precipitate and accumulate in the capillaries, blocking their gaps.

The deficiency of erythrocytes leads to their increased formation in the kidneys, and the erythrocyte germ of the bone marrow itself is reborn.

In a person, the symptoms of sickle cell anemia will be more pronounced, the poorer health. Also, the clinical manifestations of anemia are affected by the age of the patient, his living conditions and the presence of concomitant diseases. It is customary to distinguish between several groups of symptoms, including:

Symptoms of anemia due to the accelerated destruction of red blood cells.

Symptoms of anemia due to blocked blood vessels.

Symptoms of anemia provoked by a hemolytic crisis.

The disease does not make itself felt in children under 3 months. Sometimes it manifests for the first time at the age of 6 months.

Symptoms may be as follows:

The structure of the bones changes.

Joints start to hurt, swell a lot.

The sensitivity of the limbs is deteriorating, paresis is disturbing.

Hemolytic crisis is a dangerous condition for a person. With sickle cell anemia, it can be provoked by dehydration, severe hypothermia, excessive physical exertion, altitude sickness.

The following symptoms indicate a developing crisis:

Reducing the level of hemoglobin to critical levels.

Fainting states.

High body temperature.

Urine becomes dark in color.

Diagnosis of sickle cell anemia begins with a survey of the patient's complaints and anamnesis. The symptoms that the disease gives are characteristic of many pathologies, so laboratory tests are required.

The main diagnostic methods include:

Blood sampling for clinical analysis. In this case, a decrease in the level of erythrocytes and hemoglobin in the blood to levels less than 3.5-4.0 * 10 12 / l and 120 g / l, respectively, will be detected.

A biochemical blood test allows you to diagnose an increase in the level of bilirubin and free iron in the blood.

Additional diagnostic procedures include:

Performing a blood test using sodium metabisulphite. When interacting with this substance, erythrocytes release oxygen, after which their crescent shape can be visualized.

Treatment of blood with buffer compounds. HbS is poorly soluble in them.

Performing hemoglobin electrophoresis, which makes it possible to visualize mutated red blood cells. Also, this method makes it possible to distinguish a heterozygous mutation from a homozygous one.

Other examination methods that may be required:

Ultrasound examination of the liver and spleen, as well as other internal organs to detect pathological changes in them.

X-ray of the bones of the skeleton and spine.

Treatment of sickle cell anemia involves the impact on the symptoms of the disease, and is also designed to prevent the development of complications.

Therefore, when conducting therapy, you need to focus on the following principles:

Replenish the lack of red blood cells and hemoglobin.

Remove pain.

Eliminate excess iron from the body.

Eliminate the consequences of a hemolytic crisis.

A red blood cell transfusion may be required to normalize the level of red blood cells and hemoglobin. Alternatively, the patient is injected with cytostatics (hydroxyurea), which can increase the level of hemoglobin in the blood.

To relieve pain in the patient, he is prescribed analgesic drugs (Morphine, Tramadol, Promedol). When the disease is acute, it is necessary to administer drugs intravenously. After removing the exacerbation, they are used orally.

It is possible to remove excess iron from the body using certain medications, for example, with the help of Deferoxamine.

With a hemolytic crisis, the patient is shown oxygen therapy, adequate replenishment of fluid reserves, analgesics, drugs for the relief of seizures, etc.

When an infection enters the body, the patient is prescribed antibiotics, which can prevent sepsis. These can be drugs such as Cefuroxime, Amoxicillin, Erythromycin.

Be sure all patients with sickle cell anemia should adhere to the following medical recommendations:

Lead a healthy lifestyle and completely give up bad habits.

Avoid climbing.

Avoid excessive physical activity.

Drink enough water.

Avoid overheating and hypothermia.

Eat healthy foods.

There is no cure for sickle cell anemia. However, if the patient adheres to all medical recommendations, then he can live up to 50 years or more.

Complications of anemia that can provoke the death of the patient include:

Bacterial infections, which can be very severe.

Cerebral hemorrhage.

Violations in the functioning of the urinary, cardiovascular and hepatobiliary systems.

As for preventive measures, they are absent. This disease develops as a result of genetic mutations, which science is not yet able to prevent. If a particular person in the family had cases of sickle cell anemia, then before proceeding with the planning of pregnancy, a geneticist should be consulted. The doctor examines the man and woman and determines the likelihood that they will have a child with sickle cell anemia.

Education: In 2013, he graduated from the Kursk State Medical University and received a diploma in General Medicine. After 2 years, the residency in the specialty "Oncology" was completed. In 2016, she completed postgraduate studies at the Pirogov National Medical and Surgical Center.