[Genetic Analysis of Thalassemia in 22 940 Pregnant Women in Xiangxi Tujia and Miao Autonomous Prefecture].

To investigate the incidence and types of thalassemia in Xiangxi Tujia and Miao Autonomous Prefecture.Automatic capillary electrophoresis was used to screen the thalassemia phenotypes of 22 940 blood samples of pregnant women and puerperants collected in our hospital and some other medical institutions in the prefecture during 2017-2019, among which there were 3 356 cases of Tujia ethnicity, 2 821 cases of Miao ethnicity, and 2 233 cases of Han ethnicity included, whose ethnicity were indicated. The samples with positive result would undergo further genetic testing.There were 2 314 cases of suspicious thalassemia were screened from 22 940 cases by the electrophoresis, thus the positive rate was 10.1% (hematological phenotypes from some other institutions were not included). Specifically, there were 1 706 cases with HBA2 less than 2.5%, 255 cases with HBA2 ranged from 2.5% to 3.5%, which displayed abnormal hematology (MCV or/and MCH) or other abnormal bands, and 353 cases with HBA2>3.5%. There were 436 suspected positive patients in 2 314 suspicious samples received further thalassemia gene testing in our hospital, among them 48 cases were diagnosed with α-thalassemia, 85 cases with β-thalassemia, and 2 cases as compound type. The positive diagnosis rate of α-thalassemia gene test was 11.0%, β-thalassemia was 19.4%, and positive pregnant women was 31.0%.The positive rate of thalassemia screening in Xiangxi Autonomous Prefecture is roughly the same as that in other regions of Hunan. The positive predictive value of β-thalassemia screening is as high as 86%. Compared with the missed screening data, it is recommended to use hematology (MCV, MCH) method combined with capillary hemoglobin electrophoresis for thalassemia screening.湘西土家族苗族自治州22 940例孕妇地中海贫血筛查结果分析.了解湘西少数民族地区各民族地中海贫血（简称地贫）发病率及类型，探索适合湘西州地贫人群监控与预防方案，促进本地区地贫防治工作的开展.采用全自动毛细管电泳法对2017-2019年送检至本院的22 940例孕产妇血样进行地贫筛查，其中土家族3 356例，苗族2 821例，汉族2 233例，其他样本民族情况不详。对筛查阳性结果的样本进一步做基因检测.22 940例样本中筛查出可疑地贫2 314例，阳性率10.1%（部分送检血液学表型未能统计）。其中血红蛋白A2<2.5% 1 706例，血红蛋白A2在2.5%-3.5%间且血液学（平均红细胞容积或/和平均红细胞血红蛋白）异常或其他异常条带255例，血红蛋白A2>3.5% 353例。436例疑似阳性样本在本院接受了进一步的地贫基因检测，确诊α地贫48例，β地贫85例，复合型2例，α地贫基因检测阳性诊断率11.0%，β地贫基因检测阳性诊断率19.5%，筛查阳性孕妇确诊率为31.0.湘西自治州地贫筛查阳性率与湖南其他地区大致相同。β地贫筛查阳性预测值高达86%。对比漏筛数据，建议地贫筛查采用血液学（平均红细胞容积、平均红细胞血红蛋白）方法联合毛细管血红蛋白电泳法.