Sickle cell anemia is a life-threatening blood disease. It causes the clumping of blood cells and the formation of blockages in the vessels. As a consequence, a heart attack may occur, i.e. various organs is ischemic, which may lead to death. What are the causes and symptoms of sickle cell anemia? What is its treatment?

Sickle cell anemia (sickle cell anemia, drepanocytosis ) is a congenital, genetically determined blood disease that belongs to the group of hemolytic anemia. Its essence is the abnormal structure of hemoglobin - a protein that is part of red blood cells, which is responsible for the transport of oxygen to the cells.

Mutated hemoglobin not only weakly binds oxygen molecules, but also contributes to the deformation of red blood cells, which instead of the correct disk shape take the shape of crescents - sickle-shaped (so-called drepanocytes). The diseased shape of red blood cells causes their excessive destruction and thus shortened survival time. Drepanocytes only survive for a dozen or so days instead of about 100. The marrow cannot keep up with the production of new blood cells, therefore anemia develops. In addition, deformed erythrocytes tend to stick together. As a consequence, they can become trapped in small blood vessels, blocking blood from reaching different parts of the body.

The disease is most often diagnosed in mulattoes and black people, rarely in white people.

Sickle cell anemia - causes

The cause of sickle cell anemia is a mutation in the gene encoding hemoglobin, which causes changes in its structure.

Sickle cell anemia is inherited in an autosomal recessive manner. This means that both copies of the mutant gene must be obtained from the parents for symptoms of the disease to appear. If you inherit only one mutant copy, you are only a carrier of the sickle cell gene.

Sickle cell anemia - symptoms

Symptoms of sickle cell anemia appear already around the third month of the child's life:

The first symptoms of sickle cell anemia are usually swollen hands and feet, and the most frequently reported condition ispain in various locations.

  • pale skin and mucous membranes;
  • tachycardia (heart rate higher than 100 beats per minute);
  • frequent infections (as a result of weakened immunity);
  • arthritis, especially of the fingers and toes;
  • "hand-foot syndrome" - swelling of the arms and legs,
  • leg ulcers,
  • growth disturbance (resulting from disturbed blood circulation in bones);
  • pains of various locations - are the result of a heart attack, i.e. ischemia of various organs. It could be a spleen, kidney or bone infarction;

The most common direct cause of death in children with sickle cell anemia under the age of 5 is damage to the spleen as a result of obstruction in the vessels.

This will be useful to you

Carriers of defective genes are more resistant to malaria

Carriers of only one copy of the defective gene (heterozygotes) are more (but not completely) resistant to malaria. All because the diseased shape of the blood cells does not allow the development of the malaria parasite - the mutated erythrocytes are captured, destroyed and removed along with the parasite by the spleen. This explains why sickle cell anemia mainly occurs in people from malaria endemic areas (tropical and subtropical countries, especially central and west Africa).

Sickle cell anemia - diagnosis

Sickle cell anemia is diagnosed with a blood test.

Sickle cell anemia - treatment

Blood transfusion is the basic form of treatment for sickle cell disease. Supportive treatments include: antibiotic therapy, painkillers and preparations increasing the elasticity of red blood cells.

Will sickle cell anemia be treatable?

Bone marrow transplantation is another method of treating sickle cell anemia, but in adults, an anti-host-directed graft reaction (GVHD) should be taken into account. This problem was solved by scientists from the US National Institute of Diabetes and Digestive and Kidney Diseases in Bethesda. 10 people participated in their research. Each of them, instead of receiving powerful drugs that destroy the marrow, was irradiated. Then, 7 days before the procedure, patients were given alemtuzumab - a drug that destroys the cells of the immune system so that the transplant would not be rejected. Finally, the sufferers are transplanted with specific CD34 stem cells, which turn into all kinds of blood cells. They were taken from the siblings of the patients. Following surgery, patients were given another drug - rapamycin - to prevent rejectiontransplant.

The results of the research turned out to be very promising. In 9 out of 10 patients, the diseased red blood cells disappeared from the blood, and the symptoms of anemia also disappeared. It is an effective method of treating sickle cell anemia, but very expensive (especially in countries where this type of anemia occurs, mainly in African countries). Another problem is finding the right donor.

Sickle cell anemia - gene therapy

Specialists at Hôpital Necker Enfants Malades in Paris, for the first time in the world, doctors have successfully used gene therapy to treat congenital sickle cell anemia. The procedure was performed on a 13-year-old boy. Doctors removed the boy's genetic defect, first by completely destroying his bone marrow, where they are made. Then they recreated it from the boy's stem cells, but previously genetically modified them in the laboratory. This procedure involved introducing the correct gene into them with the help of a virus. The bone marrow has replenished to produce normal red blood cells. Two years after the procedure, the 15-year-old boy is well and shows no symptoms of sickle cell anemia. The specialist claims, however, that the boy cannot be "cured" yet. Further observations are necessary.

Category:

Genetic diseases