Institute of Gynecology and Obstetrics, The Third Affiliated Hospital of Guangzhou Medical College, Guangzhou, P.R. China.
Tohoku J Exp Med. 2011 Mar;223(3):223-6. doi: 10.1620/tjem.223.223.
β-thalassemia is one of the most prevalent inherited hemoglobin disorders. Compound heterozygotes or homozygous mutations of the β-globin chain gene account for severe cases of β-thalassemia that require lifelong transfusion, and make it necessary to identify β-thalassemia carries for prenatal diagnosis. The increase in hemoglobin A2 (HbA2) level is the most significant parameter in the identification of β-thalassemia carriers. HbA2, composing of two α chains and two δ chains, is a minor component of the hemoglobin present in normal adult red blood cells, accounting for about 2.5% of the total hemoglobin in healthy individuals. However, HbA2 level is also elevated in some pregnant women. This study aimed to evaluate the value of HbA2 level in the screening of pregnant women with β-thalassemia trait. Pregnant and non-pregnant women were randomly recruited who attended the prenatal care or diagnosis at our hospital located in Guangdong, a province in South China. Hemoglobin capillary electrophoresis was performed on high performance liquid chromatography to measure HbA2 levels in blood. The β-globin gene mutations were detected by the PCR-reverse dot-blot assay, and some were verified by direct sequencing. Pregnant women (n = 96) and non-pregnant women (n = 114) with normal HbA2 level (< 3.5%) had no β-thalassemia mutation. In contrast, pregnant women (n = 55) and non-pregnant women (n = 85) with elevated HbA2 level (≥ 3.5%) are β-thalassemia carriers. In conclusion, HbA2 level is a good marker for screening β-thalassemia trait in pregnant women in South China population.
β-地中海贫血是最常见的遗传性血红蛋白疾病之一。β-珠蛋白链基因突变的复合杂合子或纯合子导致严重的β-地中海贫血，需要终身输血，因此有必要识别β-地中海贫血携带者以进行产前诊断。血红蛋白 A2（HbA2）水平的升高是识别β-地中海贫血携带者的最重要参数。HbA2 由两条α链和两条δ链组成，是正常成人红细胞中存在的血红蛋白的次要成分，占健康个体总血红蛋白的约 2.5%。然而，HbA2 水平在一些孕妇中也会升高。本研究旨在评估 HbA2 水平在筛查β-地中海贫血携带者中的价值。随机招募了在位于中国南方广东省的我院进行产前检查或诊断的孕妇和非孕妇。采用高效液相色谱法进行血红蛋白毛细管电泳，以测量血液中的 HbA2 水平。采用 PCR-反向斑点印迹法检测β-珠蛋白基因突变，部分采用直接测序法进行验证。HbA2 水平正常（<3.5%）的孕妇（n=96）和非孕妇（n=114）无β-地中海贫血突变。相比之下，HbA2 水平升高（≥3.5%）的孕妇（n=55）和非孕妇（n=85）为β-地中海贫血携带者。总之，HbA2 水平是筛查中国南方人群孕妇β-地中海贫血的良好标志物。
