There are around 56000 newborns suffering from severe thalassemia in China each year, and of which at least 30000 patients have to be treated with blood transfusion. Even worse, around 5500 cases of ɑ-thalassemia dead before birth each year. South China is the high incidence area of thalassemia, which the genetic defects rate is around 2.5 % to 20 %. Especially in Guangdong and Guangxi province, the genetic defects rate is as high as 10 %~20 %.
Thalassemia is a kind of hereditary anemia caused by globin gene deficiency. At present, there are at least 81 and 186 types of mutation for ɑ and β thalassemia, respectively. The traditional therapies for thalassemia are long-term blood transfusion and stem cell transplantation (allograft), while both of them show serious side-effect and immune rejection. Gene therapy, which directly edits the mutant sites in patients’ stem cells, is a promising treatment for thalassemia and sickle cell disease.
For our thalassemia program, gene editing was employed as core technology for thalassemia therapy. The key mutant site targeted editing by CRISPR was corrected.