The hemoglobin of red blood cells is composed of two peptide chains, the alpha peptide chain and the beta peptide chain. The synthesis of the β-peptide chain is controlled by two genes, one from the father and the other from the mother. β-thalassemia is a condition in which the synthesis of the β-peptide chain is affected. Since β-peptide chain synthesis is controlled by two genes, abnormalities in one gene, or both genes, can lead to affected β-peptide chain synthesis and β-thalassemia. On the other hand, when there is an abnormality in the gene related to β peptide chain, which causes the β peptide chain synthesis to be affected, the abnormality of β peptide chain synthesis can occur in two ways. One is a gene abnormality that leads to partial inhibition of β-peptide chain synthesis; the other is a gene abnormality that leads to complete inhibition of β-peptide chain synthesis. In general: 1 gene abnormality Affected individuals are often asymptomatic, but mild anemia is present, and a small percentage may be anemic-free. The spleen is normal or mildly enlarged. They are often found during a physical examination or a family survey for thalassemia. In routine blood tests, the vast majority of those affected show a lower red blood cell count and a lower amount of hemoglobin, but often a mild anemia; individuals may be moderately anemic at some point; other individuals may have hemoglobin in the normal range and no anemia present. In addition, in routine blood tests, most of the affected patients show a decrease in mean red blood cell volume, mean hemoglobin volume, and mean hemoglobin concentration, and a small red blood cell hypochromic state; however, a small number of patients show only a decrease in mean red blood cell volume and mean hemoglobin volume, and a small red blood cell state; very few patients show normal mean red blood cell volume, mean hemoglobin volume, and mean hemoglobin concentration, and a positive red blood cell state. In some cases, the mean red blood cell volume, mean hemoglobin volume, and mean hemoglobin concentration are normal. These patients are clinically referred to as β-thalassaemia minor and do not require specific treatment. There are two states, intermediate β-thalassemia and severe β-thalassemia. If the synthesis of the beta peptide chain caused by the 2 abnormal genes is partially suppressed and the two abnormal genes are not identical, the patient tends to have moderate anemia, mild or moderate splenomegaly, and jaundice may or may not be present. Most often symptoms appear after 2 to 3 years of age. In routine blood tests, these patients have reduced hemoglobin and are often moderately anemic, or in rare cases, severely anemic. In most patients, the mean red blood cell volume, mean hemoglobin volume, and mean hemoglobin concentration are all reduced, and they present with small cell hypochromic anemia; in some patients, only the mean red blood cell volume and mean hemoglobin volume are reduced, and they present with small cell anemia. This type of patients, in clinical practice, is called intermediate beta-thalassemia. If the hemoglobin is <90g/L or less, blood transfusion is recommended to maintain the hemoglobin above 90g/L, so that the patient has a better physical condition. Splenectomy is more effective in other such patients. However, splenectomy should be performed after 5 to 6 years of age and the indications should be strictly controlled. Beta thalassemia major occurs in the presence of the following genetic abnormalities. If the synthesis of β-peptide chains is completely suppressed by 2 genetic abnormalities and the 2 abnormal genes are identical; or the synthesis of β-peptide chains is completely suppressed by 1 genetic abnormality and partially suppressed by another genetic abnormality; or the synthesis of β-peptide chains is partially suppressed by 2 abnormal genes, but the two abnormal genes are identical. In these patients, anemia is present at 3 to 12 months of age and is severe. The face is seen to be pale with jaundice, and the sclera and face may be white with yellow. The spleen is markedly enlarged. In routine blood tests, the anemia is often severe, and in rare cases may be very severe. The mean red blood cell volume, mean hemoglobin volume, and mean hemoglobin concentration are all reduced, and the patient has microcytic hypochromic anemia; because patients with beta-thalassemia major are often severely anemic, they require frequent blood transfusions. These patients are generally advised to maintain their hemoglobin above 90g/L through blood transfusion so that they can have a better physical condition. For beta thalassemia major, allogeneic hematopoietic stem cell transplantation therapy is the current method that can cure this disease. genetic testing for beta thalassemia is currently available at several medical institutions.