Thalassemia - a disease, because of which there is an infringement of hemoglobin synthesis. pathology The name literally means "anemia seashore." The disease is inherited in a recessive type, manifested as a result of genetic mutations. Knowledge that for thalassemia disease, will be useful in family planning.
Classification
For some time scientists could not figure out what is thalassemia. Only with the discovery of DNA and the properties of the polypeptide chains were able to determine a classification of diseases:
- Alpha-thalassemia. In the synthesis of the organism is suppressed α-chains of hemoglobin A. The disease is caused by heterozygous carrier of the manifest, or "silent" gene of thalassemia or homozygous embryo hydrocephalus. Sometimes develops hemoglobinopathies N.
- Beta-thalassemia. The mechanism of the organism is inhibited β-chains of hemoglobin A. It includes anemia Cooley, homo- or heterozygous D b-thalassemia.
- Gamma-thalassemia. Is suppressed hemoglobin γ-chains.
- Delta-thalassemia. Inhibition occurs δ-hemoglobin chains.
- Thalassemia, due to which broken blood protein structure responsible for the transfer of oxygen.
- Lepore-hemoglobinopathies.
- Hemoglobinopathies Constant Spring (GS).
The most common beta-thalassemia. It may be small, intermediate and large. Shallow form of the disease is characterized by low severity of symptoms. According to the severity of the pathology is divided:
- Light, (patients may survive until puberty);
- to moderate (life expectancy of patients is less than 10 years);
- to severe (death occurs in the first years of life).
Gamma and delta variants of the disease are extremely rare.
Causes
Thalassemia - a genetically determined pathology, which is inherited in an autosomal recessive basis. The immediate causes of the disease are mutations in the gene that encodes the synthesis of any particular chain of hemoglobin. Mutation is the result of abnormal RNA synthesis, the transcription of genes ineffective. Violation occurs due to mutations of the protein synthesis of hemoglobin polypeptide chains, because of which it loses its functions.
The excess or deficiency of some of the polypeptide chains of hemoglobin leads to disruption of red cell formation processes for their progressive destruction. When beta-thalassemia in red blood cells accumulate "fetal" hemoglobin. He can not carry oxygen to tissues and cells, because of which they experience anoxia.
Because bone marrow proliferation occurs a violation of the skeleton structure. As a result, oxygen starvation, anemia and ineffective formation of erythrocytes delayed child's normal development.
Homozygous thalassemia form 2 has abnormal genes that are inherited from both parents. When heterozygous thalassemia person has only one gene is inherited from one parent.
symptoms
If a child is born with thalassemia and its symptoms from the first weeks and months of life. The overall clinical picture includes the following characteristics:
- changing shape of the skull (it is almost square);
- saddle shape of the nose;
- the presence of Mongoloid cut eye (ie, eye gap narrows in a child);
- increase the upper jaw;
- enlargement of the liver, spleen (these processes are developing from the first days of life of the patient);
- hemosiderosis (accumulation in the tissues of hemosiderin pigment formed due to breakdown of hemoglobin);
- paleness and yellowness of the skin and mucous membranes;
- deposition of bilirubin stones in the bile ducts;
- fetal hydrops (this symptom is incompatible with life, because the disease is irreversibly affects the brain);
- backlog of sexual and physical development;
- malocclusion;
- weakness;
- fatigue;
- decreased immune defense.
Due to the progressive destruction of bone tissue, patients suffer fragility fractures. Hemosiderosis gradually leads to cirrhosis. Fibrotic disease (replacement of glandular connective tissue) leads to the development of insulin-dependent diabetes mellitus. Accumulation in the tissues of decomposition products of hemoglobin, anemia give rise to heart failure.
Low beta-thalassemia are asymptomatic or with minimal clinical manifestations. Patients with significantly increased spleen, anemia is diagnosed. Attention is drawn to the constant fatigue.
With the development of heterozygous alpha-thalassemia in humans do not form the alpha chain of hemoglobin. Fetal hemoglobin is also not synthesized. This kind of disease is incompatible with life. The disease leads to fetal death due to hydrocephalus or spontaneous abortion gestation.
When haemoglobinopathies H develop anemia with hemoglobin degradation phenomena, splenomegaly (enlargement of spleen), severe disruption of the structure of bone tissue.
At high beta-thalassemia develop such phenomena:
- skin lesions in the form of trophic ulcers (occur in response to impaired circulation processes);
- cirrhosis, at which the progressive substitution liver glandular tissue (connective);
- failure of the pancreas to the development of symptoms of diabetes;
- expressed as delayed sexual development;
- frequent inflammation of the lungs;
- sepsis, ie, blood poisoning.
When an intermediate form of thalassemia its first symptoms manifest themselves later in life. Children do not lag behind in physical development, their appearance does not change. The main complication of disease - enlargement of the spleen and bone loss.
Syndrome Silvestroni Bianco (minimum of beta-thalassemia) proceeds asymptomatic and diagnosed incidentally.
How is it diagnosed
Less than 5% of the population have hidden thalassemia genes, which means that it can occur in children whose parents were in the family ancestors affected by the disease. Can detect abnormalities complex diagnostics. To do this, carry out:
- general inspection of the sick child;
- Blood analysis (shows a significant decrease in hemoglobin - even up to 30 g / l, a drop of blood color index 0.5);
- Blood smears (diagnosed slightly colored red blood cells);
- Blood biochemical examination (diagnosed by increasing the amount of bilirubin, reducing the ability of blood serum to the iron binding);
- decomposition of hemoglobin on acetate-cellulose film;
- study of the processes in terms of hemoglobin biosynthesis tubes;
- bone marrow puncture;
- X-rays of the bones (found areas of osteoporosis bone striations);
- Polymerase chain reaction (it detects mutations in hemoglobin).
Treatment
If a patient develops thalassemia, its treatment depends on the severity and form of pathology:
- In severe disease varieties transfusion of whole blood or red blood cells gives short effect. These procedures are associated with risk of development of hemosiderosis.
- Side effects are much less likely to develop if the man poured the thawed or washed red blood cells. Parallel use of iron chelates.
- Iron chelate is administered continuously and under the skin. For this special pump is used. All patients with a severe form of thalassemia receive such a drug using pumps 5 times during the week throughout life. Moreover, the injection site is constantly changing, so as not to appear Lots of local tissue damage. Such treatment gives optimal effect thalassemia.
- When hemolytic crises administered small doses of glucocorticosteroid drugs.
- In case of increase of the spleen performed its removal. Surgery is not indicated for children under 5 years of age. Best of all, if such an operation is carried out for 8-10 year life.
- Most preferred is a measure of bone marrow transplantation. This is the only radical method of treatment. Find the right bone marrow donor is extremely difficult.
Patients need to follow a diet with a high content in the diet of foods rich in tannin: tea, cocoa, nuts, soy. These products significantly slow down the absorption of iron.
Apply symptomatic therapy:
- appointment of hepatoprotective drugs to support liver function;
- application of ascorbic acid (vitamin C) to activate the iron excretion.
Possible complications and prognosis
In severe pathology in tissues accumulate hemosiderin. In patients with cirrhosis of the liver, diabetes. Hemosiderosis infarction leads to death of the patient.
When haemoglobinopathies H splenectomy performed. Due to the fact that patients are likely to develop infectious complications, they need to be vaccinated against pneumococcal infections.
Prediction most varieties homozygous thalassemia unfavorable. Patients are dying in infancy or young age. In severe forms of pathology of the patient's life expectancy depends on the timely treatment and prevention of hemosiderosis.
When heterozygous form of thalassemia patients quality of life does not suffer. Bone marrow transplantation improves the prognosis.
prevention
Since thalassemia disease is genetically determined, the primary prevention includes prenatal diagnosis. If both parents suffer from thalassemia, it is necessary to conduct a study of the fetus. Sometimes the doctor recommends an abortion.
In a study of pregnant women used Fetoscopy, amniocentesis (under ultrasound guidance). Subsequently carried fetal genetic screening.
Parents who have relatives suffering from thalassemia need to address before planning pregnancy to genetics. If necessary, prescribe genetic testing.
