Thalassemia is a genetic disorder that produces mild or severe anemia due to blood disorders. This anemia is due to a lower than normal amount of reduced hemoglobin and red blood cells. Hemoglobin is the protein in blood red blood cells that carries oxygen to all parts of the body. In patients with thalassemia, the gene that codes for hemoglobin is missing or is a mutant (different from the normal gene). Severe thalassemia is often diagnosed in early childhood and remains with the patient for life. The two main types of thalassemia are alpha and beta, named mainly after the two protein chains in normal hemoglobin. The genotype of each thalassemia is passed from parent to offspring. α and β thalassemias have both mild and severe types. In some southern provinces and cities of China, 20% of the population carries the thalassemia gene. Survey data show that, in addition to Guangxi, Guangdong, Hainan and Yunnan are also high prevalence areas for thalassemia, especially in Hong Kong. Next, Fujian, Sichuan, Guizhou, Hubei and Hunan are also more common. Thalassemia genetic couple both with thalassemia gene, i.e. both are thalassemia minor, their children will have 25% possibility of being thalassemia major, 50% possibility of being thalassemia minor and another 25% possibility of being normal children; if only one of them is thalassemia minor, their children will have 50% possibility of being normal children and 50% possibility of being thalassemia minor, and no thalassemia major child. However, just because a couple has one or more thalassaemia-free children does not mean that they do not carry the thalassemia gene or that their children will not be affected in the future. How to prevent and treat thalassemia Thalassemia can be cured by stem cell or bone marrow transplantation, but it can be prevented preemptively by preimplantation genetic diagnosis. Preimplantation Genetic Diagnosis (PGD), also known as third-generation IVF, is a prenatal diagnostic technique developed by combining ART and molecular biology techniques, which is based on IVF technology and can be used to check whether an embryo carries genes with genetic defects. After the sperm and egg are combined in vitro to form a fertilized egg and develop into an embryo, genetic testing is performed before its implantation in the uterus in order to enable IVF with in vitro fertilization to avoid some genetic diseases.