What Is Beta Thalassemia?

-mediterranean anemia refers to a group of hemoglobinopathy in which -chain synthesis is partially or completely inhibited. Patients are asymptomatic at birth, more than those in infancy, and 50% are affected within 3 to 6 months after birth, with occasional neonatal onset. The earlier the age of onset, the more severe the condition. Severe chronic progressive anemia depends on blood transfusion to support life. Blood transfusion is performed once every 3 to 4 weeks, which becomes increasingly obvious with age.

beta-thalassemia

Overview of beta-thalassemia

Beta-thalassemia symptoms and signs

Patients are asymptomatic at birth, more than those in infancy, and 50% are affected within 3 to 6 months after birth, with occasional neonatal onset. The earlier the age of onset, the more severe the condition. Severe chronic progressive anemia depends on blood transfusion to support life. Blood transfusion is performed once every 3 to 4 weeks, which becomes increasingly obvious with age. With skeletal changes, it first occurs in the metacarpals, then the long bones, ribs, and finally the skull, forming a special face (Down's face): large head, forehead protrusion, slightly high two ridges, low nose bridge, widening eye distance, eyelid edema . Skin pigmentation. Loss of appetite, stagnation of growth and development, liver and spleen are gradually enlarged, and the spleen is obvious, reaching the pelvic cavity. Children often have bronchitis or pneumonia. Corresponding symptoms of organ damage caused by excessive iron deposition in the myocardium and other organs such as the liver and pancreas caused by hemosiderinosis, the most serious of which are heart failure and liver fibrosis and liver failure Is one of the important reasons leading to the death of children. If untreated, the disease will die before the age of 5 years.

-thalassemia diagnostic test

Diagnosis: The diagnosis can be confirmed based on clinical manifestations and blood tests, especially increased HbF content and family surveys. Those who have the conditions can further perform peptide chain analysis or genetic diagnosis.

Laboratory inspection:

1. Hb 100-120g / L, red blood cells <2.0 × 10 / L, red blood cells of varying sizes, showing small cell hypochromic anemia, lightly stained in the center. Peripheral blood smears showed obvious abnormalities of red blood cells, including pear-shaped, teardrop-shaped, small spheres, triangles, targets, and fragments. Basophilic stippled red blood cells, polytropic erythrocytes, and increased nucleated red blood cells. Reticulocytes increased (0.1). The number of white blood cells and platelets increased, accompanied by hypersplenism.

2. Bone marrow like nucleated red blood cell hyperplasia is extremely active. The ratio of granulocytes to red is reversed, mainly middle and young red blood cells, small cell body, nuclear shrinkage, less blue cytoplasm, and methyl violet staining showing that young red blood cells contain inclusion bodies (Strand precipitation only).

3. Erythrocyte saline permeability test Erythrocyte osmotic fragility is reduced, and 0.3% to 0.2% or lower is required for complete hemolysis.

4. HbF determination This is an important basis for the diagnosis of severe -globin dysplasia anemia. HbF content increased slightly (<5%) or significantly increased (20% to 99.6%); HbA2 often decreased, normal or moderately increased, HbA 23.5% to 8.0%.

5. Peptide chain analysis The content of , , , and peptide chains can be determined by high performance liquid chromatography. In Cooley anemia, the / ratio is <0.1 (normal value is 1.0 to 1.1). Because the disease is mostly point mutations, PCR and ASO can often be used to determine the mutation point. The thalassemia gene mutations in different ethnic groups in China are different. The mutation genes in the southern Han are CD41-42 (-TCTT), CDL7 (A T), IVS--654 (C T), and TATA-box28 (A G), accounting for 85% to 90%. Double heterozygous mutation combinations can reach nearly 100 species.

6. The content of vitamin E in other plasma and red blood cells decreased significantly, which was positively correlated with the condition; the superoxide anion free radicals increased.

Other auxiliary examinations: routine X-ray, B-ultrasound, electrocardiogram and other examinations. On bone X-ray examination, the bone marrow cavity is widened, the cortex is thinned and osteoporosis, the internal and external plates of the skull are thinned, the plate barriers are widened, and short hair-like spurs are formed.

Beta-thalassemia treatment options

1. Principles of treatment No treatment is needed for mild thalassemia; intermediate alpha thalassemia should avoid infection and use of peroxidative drugs, and those with moderate anemia with splenomegaly can undergo spleenectomy. Intermediate beta thalassemia is generally not transfused, but in the case of infection, stress, surgery, etc., red blood cell concentration can be appropriately given; severe beta thalassemia, high blood transfusion combined with iron removal is the basic treatment; hematopoietic stem cell transplantation (Including bone marrow, peripheral blood, umbilical cord blood) is the only clinical method to cure the disease, and those who have the conditions should strive for radical surgery as soon as possible.

2. Transfused red blood cells

(1) Low volume blood transfusion: simple blood transfusion or red blood cell transfusion leads to hemochromatosis. Moderate amount of blood transfusion therapy to maintain hemoglobin at 60 ~ 70g / L. Practice has proved that although this blood transfusion method is expected to get rid of the threat of recent deaths, the quality of life of patients is getting worse with age. A considerable number of patients died of organ failure within the second decade.

(2) High volume blood transfusion:

Advantages of high-volume transfusion of concentrated red blood cells: correction of hypoxia in the body; reduction of intestinal iron absorption; suppression of splenomegaly; correction of slow growth and development of children. Method: Repeat the infusion of concentrated red blood cells to make the hemoglobin content of the child reach 120 140g / L, and then infusion of concentrated red blood cells 10 15ml / kg every 3 4 weeks with Hb80 90g / L to maintain the Hb content Above 100g / L.

3. Iron chelator due to long-term high-volume blood transfusion, strong bone marrow erythropoiesis, "ineffective erythropoiesis" and increased gastrointestinal iron absorption, often lead to iron overload in the body, which is easily associated with hemochromatosis, and damage to the functions of the heart, liver, kidney and endocrine organs When the body's iron accumulates to more than 20g, there can be obvious manifestation of poisoning, so it should be treated with iron chelator.

4. Hematopoietic Stem Cell Transplantation (HSCT) HSCT is currently the only method to cure the disease clinically. HSCT includes bone marrow transplantation (BMT), umbilical cord blood transplantation (UCBT), peripheral blood hematopoietic stem cell transplantation (PBSCT), and intrauterine hematopoietic stem cell transplantation (IUSCT). So far, 1200 cases of HSCT have been successfully carried out in the world, including more than 1,000 cases of BMT, 10 cases of PBSCT, about 30 cases of UCBT, and 2 cases of IUSCT. The study found that HSCT of severe thalassemia has its own characteristics.

5. Splenectomy, most splenic embolisms

6. Gene therapy corrects the expression of pathogenic genes at the molecular level, that is, gene therapy.

-thalassemia prevention and prognosis

Prognosis: Major complications of -thalassemia are often an important cause of death in children. If untreated, they die before 5 years of age. Intermediate and mild thalassemias can survive long-term if properly treated.

Prevention: Jiu u12289 _uc2 has carried out eugenic and eugenic work to reduce / control the inheritance of the thalassemia gene.

1. Screening for thalassemia before marriage and avoiding the marriage of patients with mild thalassemia can significantly reduce the chance of birth of patients with severe / intermediate thalassemia.

2. Promote prenatal diagnosis technology. For both parents or thalassaemia gene carriers, at 4 months of pregnancy, fetal villi, amniotic fluid cells or umbilical cord blood are collected to obtain genomic DNA. Polymerase chain reaction (PCR) technology is used for high-risk fetuses. For prenatal diagnosis, pregnancy should be terminated in severe / intermediate children.

Screening for thalassemia before marriage and avoiding the marriage of patients with mild thalassemia can significantly reduce the chance of birth for patients with severe / intermediate thalassemia. Promote prenatal diagnosis technology. For parents with thalassaemia gene carriers, at 4 months of pregnancy, fetal villi, amniotic fluid cells or cord blood are collected to obtain genomic DNA. Polymerase chain reaction (PCR) technology is used to produce high-risk fetuses. Before diagnosis, severe / intermediate children should terminate pregnancy.