OBJECTIVE:

To investigate the spectrum of β -thalassemia mutations in Guizhou Province.

METHODS:

For 542 individuals suspected to have β -thalassemia by decreased mean corpuscular volume (MCV) and corpuscle hemoglobin (MCH) by routine blood test and hemoglobin electrophoresis, reverse dot blot hybridization (RDB) was performed to detect 17 known β -thalassemiamutations, including 8 common and 9 rare mutations. For cases where no mutation was identified, the entire human β -globin gene was screened to find other rare mutations. The distribution and frequencies of detected β -thalassemia mutations were then analyzed.

RESULTS:

A total of 460 individuals were diagnosed as β -thalassemia by DNA analysis, which included 352 heterozygotes, 67 compound heterozygotes and 41 mutant homozygotes. A total of 12 β -thalassemia mutations were detected in these individuals. The mutations have ranked from high to low frequency as: CD17(40.74%), CD41-42 (33.69%), IVS-II-654(13.76%), -28(3.70%), β E(3.35%), CD71-72(1.94%), CD43 (1.06%), IVS-I-1(0.71%), CD27-28(0.35%), -29(0.35%), CAP(0.18%), and CD121(0.18%). The former six mutations have accounted for 97.18% of all. CD121(GAA> TAA) detected from a heterozygote, as a dominant mutation, has been firstly found in the Chinese population.

CONCLUSION:

The spectrum of β -thalassemia in Guizhou Province showed certain distinct characteristics, with CD17 being the most common mutation. The newly discovered mutation of CD121 has expanded the spectrum of β -thalassemia in Chinese population. Our result may provide valuable information for the prevention and control of β -thalassemia in Guizhou.