Objective: To investigate characteristics of silent alpha thalassemia genes in child-bearing adults in Guangdong, in order to provide data for the prevention and control of hemoglobin H disease.
Methods: A total of 8 752 cases were collected from January 2016 to December 2020. Gap-PCR was used to detect the deletional of α-thalassemia mutations (-α3.7, -α4.2), while PCR reverse dot blot hybridization assay (RDB) was used to detect the non-deletional α-thalassemia mutations (Hb CS, Hb QS and Hb Westmead).
Results: Among 8 752 subjects, 717 cases of silent α-thalassemia were detected, the detection rate was 8.19%, including 555 cases of deletional α-thalassemia (77.41%) and 162 cases of non-deletional α-thalassemia 22.59%. The mean corpuscular volume (MCV) of deletional silent α-thalassemia was (82.09±4.10) fl, and mean corpuscular hemoglobin (MCH) was (27.03±1.37) pg, which both were over the diagnostic cut-off value for thalassemia. The MCV of non-deletional silent α-thalassemia was (81.07±4.93) fl, and MCH was (26.77±2.20) pg. According to the diagnostic criteria, if using MCV<82 fl or (and) MCH<27 pg as a positive criteria for screening thalassemia in the childbearing age, the screening sensitivity was 53.14% and different in different genotype, among which ααQS/αα was 100%, -α3.7/αα, -α4.2/αα, ααCS/αα and ααWS/αα was 62.15%, 63.41%, 44.83% and 39.62%, respectively. Namely, nearly half the carriers of such mutations might have escaped detection as a result of their screening strategy.
Conclusion: When a couple is preparing for pregnancy, if one of them has been determined to be mild α-thalassemia or hemoglobin H disease, other half is necessary to carry out silent α thalassemia detection to prevent the birth of children with hemoglobin H disease even if MCV>82 fl and MCH>27 pg.
题目: 广东地区育龄人群静止型α地中海贫血基因型分析研究.
目的: 探讨广东地区育龄人群静止型α地中海贫血（简称地贫）基因携带特征，为血红蛋白H病的有效防控提供理论依据。.
方法: 对2016年1月至2020年12月8 752例育龄人群进行α地贫基因检测。采用Gap-PCR方法检测缺失静止型α地贫基因，检测类型包括-α3.7、-α4.2；采用PCR-反向斑点杂交技术检测非缺失静止型α地贫基因，检测位点包括Hb Constant Spring（αCS）、HbQuong Sze（αQS）和HbWestmead（αWS）。.
结果: 8 752例就诊受检者 中，检出静止型α地贫717例，检出率为8.19%；其中缺失静止型α地贫有555例（77.41%），非缺失静止型α地贫162例（22.59%）；缺失静止型α地贫携带者平均红细胞体积（MCV）均值为（82.09±4.10）fl，平均红细胞血红蛋白含量（MCH）均值为（27.03±1.37）pg，均大于地贫初筛阳性指标；非缺失静止型α地贫携带者MCV均值为（81.07± 4.93）fl，MCH均值为（26.77±2.20）pg。根据地贫筛查指标MCV<82 fl或（和）MCH<27 pg进行育龄人群α地贫基因筛查，总灵敏度为53.14%；其中，ααQS/αα基因型灵敏度达100%，-α3.7/αα、-α4.2/αα、ααCS/αα、ααWS/αα基因型灵敏度分别为62.15%、63.41%、44.83%、39.62%，即若以现行的筛查标准进行地贫基因携带者筛查，则将近一半的静止型α地贫携带者被漏检。.
结论: 准备生育的夫妻双方，如果一方已确定为轻型α地贫基因携带者或血红蛋白H病患者，而另一方即使MCV>82 fl、MCH>27 pg，也有必要进行静止型α地贫基因检测，防止血红蛋白H病患儿出生。.
Keywords: child-bearing adult; genotype detection; silent α thalassemia.