Gene Mutation Types of Thalassemia in Chongzuo Childbearing-age Population of Guangxi Zhuang Autonomous Region of China / 中国实验血液学杂志

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 -α3.7, and 0.24% for --Thai. Among 32 α-thalassemia genotypes, the most common five were --SEA/αα, -α3.7/αα, αCSα/αα, -α4.2/αα and αWSα/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, -α3.7/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/-α3.7 combining -28/IVSI-1 (Hb: 83 g/L) and 1 case of -α3.7/αα combining CD41-42/ CD41-42 (Hb: 110 g/L) were detected without history of blood transfusion, while 1 case of αWSα/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.

Epidemiological investigation and genotype of thalassemia on middle school students in Chongzuo, Guangxi / 中华流行病学杂志

Objective To investigate the carrier ratio and the genotype of thalassemia among students of secondary school in Chongzuo, Guangxi. Methods From June 10-20,2008 among 7 regions of Chongzuo, 1 secondary school was randomly chosen from each region, and the number of student volunteers was determined by 0.5‰ proportion of the local population size. 1097 students were screened, including 515 boys and 582 girls of 12-16 year olds. Among them, 968 cases were Zhuang (438 boys and 530 girls) 128 cases were Han (76 boys and 52 girls) and one case was Yao nationalities (boy). Analysis of blood cells was detected by Cell Dyn 1700 automatic hemocyte analysator while hemoglobin F (HbF) and hemoglobin A2 (HbA2) were detected by hemoglobin autoanalyse variant. Among those with HbA2≥ 4% that belonged to β-thalassemia before α and β-thalassemia gene were analyzed to identify the genotypes. IfHbA2 was <4% but MCV≤80 fl, α-thalassemia gene was analyzed. Results Among 1097 cases,218 wereα-thalassemia (19.87%), 50 were β-thalassemia (4.56%) and 13 were combination of α β-thalassemia (1.19%). The overall detected ratio was 25.62%. 133 cases with thalassemia were boys (25.83%) and 148 were girls (25.43%) with no significant difference(P>0.05). 255 cases of thalassemia were Zhuang (26.34%), and 25 were Han nationality (19.52%). The detected ratio among Zhuang nationality was higher than in Hun nationality and with significant difference statistically (P<0.01). 3 kinds of deletion (-α3.7/,-α<4.2>/, --SEA/) and another 3 kinds of non-deletion (αα CS/, αα WS/, αα QS/) α-thalassemia genotype were identified, with a higher rate of ααWS/. Among the β-thalassemia genotype, CD41-42 appeared the most common genotype. MCV of thalassemia was lower than in the controls, with significant difference (P<0.01). 78-90 fl of α-thalassemia was detected from the MCV specimen. If taken MCV<79 fl as the positive phenotype of thalassemia, 32 cases were misdiagnosed. The rate of missed diagnosed cases was 2.97%. Conclusion Rate of thalassemia carder among students of secondary school in Chongzuo, Guangxi was considered to be high, especially those belonged to Zhuang nationality were higher than the Hans. The carrier rate of ααWS/was higher, with CD41-42 the most common genotype.