Objective: To study the genotype of β-thalassemia in Chongqing area. Methods: 24 patients with β-thalassemia were diagnosed by hemoglobin electrophoresis from patients with hypochromic microcytic anemia . Fluorescence dot blot hybridization was performed in all patients and their parents by 8 most commonly used oligonucleotide probes in China. Results: 14 patients withβ-thalassemia major

7 patients withβ-thalassemia minor and 3 patients withβ-thalassemia combined with HbE were diagnosed . 10 kinds of gene mutations were identified among these patients. The genotypes inβ-thalassemia minor are all heterozygotes. One homozygote and 13 double heterozygotes were found with patients inβ-thalassemia major. Clinical features of β-thalassemia major include early episode

severe anemia and increased HbF level. Long-term transfusion was all required for these patients to maintain the life and growth. Among 3 patients withβ-thalassemia combined with HbE

one is with thalassemia major and the rest are with thalassemia intermedia. Conclusion: The clinical features of β-thalassemia is closely related to the genotype. Double heterozygote is the most common genotype in Chongqing area and the parents of the patients are all carrier. The mutation of CD17

IVS-Ⅱ-654 and CD71-72 are the most common genotypes in this study. The clinical features in the patients withβ-thalassemia combined with HbE varied greatly.