The Study On The Incidence And Genotypes Of α-thalassemia In The Children In Nanning, Liuzhou And Baise Areas

ObjectiveTo investigate the incidence and genotypes ofα-thalassemia (α-thal) in the children in Nanning, Liuzhou and Baise Areas. To study the differences in the ethnic group and areas.MethodsTotal of 1789 children aged 3-6.5 years old in Nanning, Liuzhou and Baise areas were studied. Venous blood was anti-coagulated by ACD, and to be examined by blood count, hemoglobin electrophoresis and quantified by highly effective liquid chromatography. Theα-thal genotypes were detected by polymerase chain reaction (PCR) and reversed dot hybridization. The data were statistical processed by SPSS 13.0 statistical software.Result1. Among 1789 children, 224 cases were detected asα-thalassemia. The incidence ofα-thalassemia was 12.52%.2. All of the 224 casesα-thalassemia include:①130 cases were lightα-thalassemia (58.03%): 124 cases with Southeast Asia type ofα-thalassemia (--SEA/αα), account for 55.36%; 2 cases with heterozygotes of Thailand deletional type ofα-thalassemia ( --Thai/αα)(0.89%); 2 cases with homozygous of -α3.7 deletionalα-thalassemia (-α3.7 /-α3.7, 0.89%); 1 cases with homozygous of -α4.2 deletionalα-thalassemia (-α4.2 /-α4.2, 0.45%); 1 case with Double heterozygotes (-α4.2 /-α3.7, 0.45%).②85 cases were silent carrier state (37.95%): 41 cases with heterozygotes of -α3.7 deletionalα-thalassemia (-α3.7/αα, 18.30% ) ; 19 cases with heterozygotes of -α4.2 deletionsα-thalassemia (-α4.2/αα)(8.48%); 24 cases with homozygous of Hb Constant Spring (αCSα/αα,10.71%); 1 cases with homozygous of Hb Quong Sze (αQSα/αα,0.45%).③9 cases were Hb H disease (4.02%). The mutations included: double heterozygotes of the Southeast Asia type of deletionalα-thalassemia (--SEA) combined with -α3.7 deletionalα-thalassemia (-α3.7), -α4.2 deletionalα-thalassemia , or Hb CS. There were 3 cases with --SEA/-α3.7(1.34%); 2 cases with --SEA/-α4.2(0.89%)and 4 cases with --SEA/αCSα(1.79%).3. The cases and incidence ofα-thalassemia among different areas were as follows: 93 cases in Baise(16.15%),48 cases in Nanning(10.91%),83 cases in Liuzhou(10.74%).4. The cases and incidence ofα-thalassemia among different ethnic groups were as follows: 71 cases in Han nationality(0.09%),121 cases in Zhuang nationality(0.13%).5. The cases and incidence ofα-thalassemia between different genders were as follows: 128 cases in boys(13.06%),96 cases in girls(11.87%).Conclusions1.The incidence ofα-thalassemia was 12.52% among 1789 children in Nanning, Liuzhou and Baise Areas. 2. The genotypes in the children were --SEA/αα,-α3.7/αα,-α4.2/αα,αCSα/αα; --SEA/αCSα,--SEA/-α3.7 ,--SEA/-α4.2 ,-α3.7 /-α3.7 ,--Thai/αα,-α4.2 /-α4.2 ,-α4.2 /-α3.7 andαQSα/αα.3. The common genotypes in this study in three areas were --SEA/αα,-α3.7/αα,-α4.2/ααandαCSα/αα;while the rare genotypes were --Thai/ααandαQSα/αα.4.The incidence of Zhuang children was higher than that in Han children. There were more kind of genotypes in Zhuang children than that in Han children. This Suggested thatα-thalassemia in Zhuang nationality were more complex.5.The incidence ofα-thalassemia in Baise was higher than that in Nanning and Liuzhou areas.6.It was the first report that Thailand deletional type ofα-thalassemia was detected in children in China.7.The results can be benefit for the genetic counseling in the children, in these areas.