Alpha thalassemia in children is a group of hemolytic anemias caused by the α-globin chain synthesis disorder due to the deletion or functional defect (point mutation) of the α-globin gene. It is a type of thalassemia. Thalassemia, also known as "thalassemia", is caused by the blockage or complete inhibition of the synthesis of one or more globin peptide chains, resulting in abnormal Hb composition and chronic hemolytic anemia. According to the different types of globin gene deletions or defects, the corresponding inhibition of globin chain synthesis is caused. Thalassemia can be divided into α-thalassemia, β-thalassemia, δ-thalassemia, γ-thalassemia and the rare β-thalassemia; the first two types are common. They are all autosomal incomplete dominant inheritance.