[Gene Mutation Types of Thalassemia in Chongzuo Childbearing-age Population of Guangxi Zhuang Autonomous Region of China].

Objective: To investigate the gene mutation and genotype distribution of thalassemia in the population of childbearing age in Chongzuo area of Guangxi.
Methods: Six α-thalassemia and 17 β-thalassemia gene mutations common in Chinese were detected by gap-polymerase chain reaction (gap-PCR) combined with agarose gel eletrophoresis and reserve dot bolt hybridization in 29 266 cases of child-bearing age suspected of thalassemia.
Results: A total of 19 128 (65.36%) cases were identified with thalassemia. The detection rate of α-thalassemia, β-thalassemia and α-combining β-thalassemia was 45.25% (13 242/29 266), 15.47% (4 526/29 266) and 4.65% (1 360/29 266), respectively. A total carrying rate of 8 kinds of α-thalassemia gene mutations was 26.74% (15 649/58 532), including 12.51% for -- ^SEA , followed by 5.70% for -α ^3.7 , and 0.24% for -- ^Thai . Among 32 α-thalassemia genotypes, the most common five were -- ^SEA /αα, -α ^3.7 /αα, α ^CS α/αα, -α ^4.2 /αα and α ^WS α/αα, accounting for 47.27%, 18.31%, 8.56%, 8.52% and 7.91%, respectively, as well as 0.97% for -- ^Thai /αα. A total carrying rate of 13 kinds of β-thalassemia gene mutations was 10.07% (5 897/58 532), including 3.63% for CD41-42 , followed by 2.55% for CD17 , and 0.003% for -50 (G>A). Among 17 β-thalassemia genotypes, the most common six were CD41-42/N , CD17/N, CD71-72/N, CD26/N, 28/N and IVSI-1/N , accounting for 36.15%, 25.81%, 9.43%, 8.18%, 8.09% and 7.75%. The homozygous genotype CD26/CD26 [hemoglobin (Hb): 121 g/L] and -28/-28 (Hb: 56 g/L) were respectively detected in one case, and double heterozygous genotype were detected in 5 cases, including 3 cases of CD41-42 /CD26 (Hb: 41 g/L, 51 g/L, 63 g/L, respectively), 1 case of -28/IVSI-1 (Hb: 53 g/L), and 1 case of CD71-72/CD26 (Hb: 89 g/L), in which patients with moderate or severe anemia had a history of blood transfusion. Among 104 α-combining β-thalassemia genotypes, the most common were -- ^SEA /αα, -α ^3.7 /αα combining CD41-42/N and -- ^SEA /αα combining CD17/N , accounting for 12.13%, 9.63% and 9.26%, respectively. In addition, 1 case of -- ^SEA /-α ^3.7 combining -28/IVSI-1 (Hb: 83 g/L) and 1 case of -α ^3.7 /αα combining CD41-42 / CD41-42 (Hb: 110 g/L) were detected without history of blood transfusion, while 1 case of α ^WS α/αα combining CD41-42 /CD17 (Hb: 79 g/L) and 1 case of -- ^SEA /αα combining CD17/-28 (Hb: 46 g/L) were detected with history.
Conclusions: The detection rate of thalassemia genes is high and the mutations are diverse in the population of childbearing age in Chongzuo area of Guangxi. The common deletion genotype is -- ^SEA /αα in α-thalassemia and CD41-42/N in β-thalassemia, and deletion genotype -- ^Thai is not rare. There is a certain incidence of intermediate and severe β-thalassemia, and most patients require transfusion therapy. The results are beneficial for genetic consultation and intervention of thalassemia.