国际移植与血液净化稿件信息
来宾市兴宾区孕前优生健康检查夫妇地中海贫血结果分析
林梅 区玉星 陈世新
广西壮族自治区来宾市妇幼保健院（广西来宾） 546100
【摘要】目的：调查来宾市兴宾区参加孕前优生健康检查新婚夫妇地中海贫血的基因携带率、基因突变类型及其分布特征,为制定有效可行的婚育人群地贫防控计划提供依据。方法：选择2017年参加来宾市兴宾区免费孕前优生健康检查的新婚夫妇6498例当地育龄人群采用血细胞五分类和血红蛋白电泳分析指标筛查出地中海贫血高危人群，采用跨越断裂点的聚合酶链式反应（Gap-PCR）技术和PCR结合反向点杂交（PCR-RDB）技术诊断并分析α、β地贫阳性病例的基因突变类型及频率。对携带同型地中海贫血基因的待孕夫妇进行优生咨询指导,重点跟踪随访。结果：地贫初筛阳性1432例，初筛阳性率为22.04%（1432/6498），基因诊断确定为地贫基因阳性920例，阳性率为14.16%（920/6498）。其中检岀α-地贫593例（64.45%），基因突变类型 19种；β-地贫260例（28.26%），基因突变类型9种；αβ复合型地贫67例（7.28%），基因突变类型 17种。对206对夫妇双方为同型基因高危地贫孕产妇进行产前诊断，产前诊断率为80.47% ( 206 /256) 检出正常胎儿58 例，检出率28.16% ( 58 / 206)；检出各类α地贫静止型胎儿18例，检出率8.74% (18 /206)；检出各类α地贫标准型胎儿32例，检出率15.53% (32 /206)；检出各类轻型β地贫胎儿25例，检出率12.14% (25 /206)；检出各类α复合β地贫轻型13例，检出率6.31% (13 /206)；检出各类重型/中间型(α地贫，β地贫或α复合β地贫等)地贫胎儿60 例，检出率29.13% (60 /206)。经伦理道德宣教，提供知情选择，有52例中重型地贫胎儿终止妊娠,部分中间型α地贫胎儿在非指令遗传咨询后选择继续妊娠。结论：来宾市兴宾区是地贫高发区,人群携带率也较高，本研究描述了来宾市兴宾区育龄人群常见的α-和β-地贫的发生率和较为详细的基因突变谱,丰富了本地区地中海贫血的流行病学资料。为制订地贫的预防计划和开展优生工作提供参考。认为对携带同型地中海贫血基因的待孕夫妇进行遗传咨询,对高风险夫妇免费进行产前诊断,能有效降低重型地贫儿发生率。对预防出生缺陷有重要意义。
【关键词】 孕前优生；地中海贫血； 怀孕风险；预防出生缺陷
Analysis of results of pre-pregnancy eugenics health examination for couples with thalassemia in Xingbin District, Laibin City
Ou Yu Xing Lin mei, Chen shixin
Laibin guangxi zhuang autonomous region maternal and child health care (guests) in guangxi 546100
【abstract】 Objective: to investigate the gene carrying rate, gene mutation type and distribution characteristics of thalassemia of newlyweds who participated in preconception health examination in xingbin district of laibin city, and to provide the basis for the effective and feasible plan of poverty prevention and control of marriageable population. Methods: 6498 newly married couples who took part in the free pre-pregnancy health check-up in Xingbin District, Laibin City in 2017 were screened by blood cell five classification and hemoglobin electrophoresis analysis index to detect the high-risk group of thalassemia. The polymerase chain reaction(Gap-PCR) technology across the fracture point and the PCR combined with reverse point hybridization(PPR-RDB) technique were used to diagnose and analyze the types and frequencies of gene mutations in positive cases of alpha and beta poverty. To carry out eugenic counseling and guidance for pregnant couples carrying the same type of thalassemia gene, follow up with emphasis. Results: 1432 cases were positive at the beginning of poverty, 22.04 % were positive at the first screening(1432/6498), 920 cases were positive for the gene of poverty, and 14.16 % were positive at the first screening(920/6498). Among them, 593 cases(64.45 %) of α-land poverty were detected, and 19 types of gene mutations were detected; There were 260 cases of β-land poverty(28.26 %) and 9 types of gene mutations; There were 67 cases(7.28 %) of αβ compound poverty and 17 types of gene mutations. The prenatal diagnosis of 206 couples for poor mothers with the same type of gene was 80.47 %(206/256) and 58 normal fetuses were detected. The detection rate was 28.16 %(58/206). 18 cases were detected of various types of alpha still fetuses, and the detection rate was 8.74 %(18/206); 32 cases of standard fetuses of various types of alpha poverty were detected, and the detection rate was 15.53 %(32/206); 25 cases of various types of light β-poor fetuses were detected, and the detection rate was 12.14 %(25/206); 13 cases of light poverty of various types of alpha compound beta were detected, and the detection rate was 6.31 %(13/206); 60 cases of severe / intermediate(alpha poverty, beta poverty or alpha compound beta poverty, etc.) fetal poverty were detected with a detection rate of 29.13 per cent(60/206). Through ethical and moral education, informed choices were provided. In 52 cases, the moderately and heavily impoverished fetus terminated the pregnancy, and some intermediate alpha poor fetuses chose to continue the pregnancy after non-directed genetic counseling. Conclusion: the high incidence of poverty and high population carrying rate in xingbin district of laibin city, this study described the incidence of common alpha-and beta-poverty in the population of childbearing age in xingbin district of laibin city and detailed genetic mutation spectrum, enriched the epidemiological data of thalassemia in the region. It provides a reference for the formulation of prevention plans for poverty and the development of eugenics. It is believed that genetic counseling for pregnant couples carrying the same type of thalassemia gene and free prenatal diagnosis for high-risk couples can effectively reduce the incidence of children living in severe poverty. It is important to prevent birth defects.
【key words】 Preconception eugenics; Mediterranean anaemia; Risk of pregnancy; Prevention of birth defects
地中海贫血(以下简称地贫)是由于珠蛋白基因的缺失或缺陷引起血红蛋白珠蛋白肽链中的一种或几种合成不平衡所致的一组遗传性溶血性疾病。调查显示，广西人群中地贫基因携带率为20%左右，远远高于全国的其他地区，是广西危害最大的遗传性疾病。本研究以国家卫生和计生委实施“国家免费孕前优生健康检查项目”来宾市兴宾区新婚夫妇人群为对象，依靠国家卫生计生委搭建的孕前优生健康检查信息管理平台，免费为新婚夫妇进行地贫基因筛查、地贫基因诊断，为同型地贫夫妇提供咨询指导、跟踪随访等优质服务。有效降低了重症地贫胎儿的出生。
1 资料与方法
资料来源 收集 2017年1月-2017年12月在来宾市兴宾区进行正规免费孕前检查的夫妇，夫妇双方均为当地户籍，共获得地贫疑似病例共6498例 ，其中女性3586例，其中男性年龄 22-45（27.1±2.6）岁；女性年龄 21-44（28.5±2.2）岁，所有受检夫妇均签署了免费孕前优生健康检查知情同意书。
1.2 方法
1.2.1 地贫血液学筛查方法：血细胞分析用日本希森美康XN全自动血细胞分析仪；血红蛋白组分分析用美国BIO-RAD VARIANTⅡ全自动血红蛋白组分分析仪，每份样本均取EDTA-2K抗凝静脉血2ml，所用试剂均是厂家配套试剂。以红细胞平均体积 ( MCV) ≤ 82fl 或/和平均血红蛋白量 ( MCH) ≤ 27 pg ,或/和HbA2≤2.4，或/和HbA2≥3.5为血液学指标筛查出地中海贫血高危人群[1]。
1.2.2 地贫基因诊断方法：全血DNA用厦门致善生物科技股份有限公司Lab-Aid820全自动DNA提取仪提取，用厦门致善生物科技股份有限公司的试剂批号为170104、170606的试剂，每份样本均取EDTA-2K抗凝静脉血2ml。中国人常见的4种α缺失（包括--SAE/、--THAI/、-α3.7/、-α4.2 /）用Gap-PCR的方法检测，用深圳益生堂生物企业有限公司提供的试剂批号为20170102、20170602的试剂进行检测，并且按照试剂说明书判读结果；中国人常见的3种α点突变（包括-αWS /、-αCS / 、-αQS /）和中国人常见的17种β点突变（包括41-42M/N、654M/N、-28M/N、71-72M/N、17M/N、βEM/N、43M/N、-29M/N、31M/N、-32M/N、IVS-I-1M、27/28M、-30M、14-15M、CAPM、IntM、IVS-I-5M）用PCR-RDB的方法检测，用亚能生物技术(深圳)有限公司提供的试剂批号为201701004、201706004的试剂进行检测，并且按照试剂说明书判读结果。
1.2.3 统计学处理 采用描述性方法，分析 α 和 β 地中海贫血基因突变类型及频率分布。
2 结果
2.1 基因突变阳性率 本资料检测6498例育龄人群，检岀地贫初筛阳性1432例，初筛阳性率22.04%，对初筛阳性者进行地贫基因诊断，结果检岀920例为地贫基因阳性，阳性率为14.16%。其中诊断为α-地贫593例（64.45%），诊断为β-地贫为260例（28.26%），诊断为αβ复合型地贫67例（7.28%）。920例地贫患者各基因构成比见表1。
表1 920例地贫患者各基因构成比（%）
|
基因类型 阳性人数 % |
|
α-地贫 593 64.45 β-地贫 260 28.26 αβ复合型地贫 67 7.28 合计 920 100.00 |
2.2 α-地贫基因突变类型及分布 593例α-地贫基因阳性患者中，检出基因突变类型 19种, α缺失型基因以--SEA为主（47.22%），α突变型基因以αCSα为主（13.66%），--SEA 、-α3.7、αCSα三个基因类型占所有α-地贫基因阳性患者的80%左右，又以--SEA 型占的比重最多，为47.22%，近一半。α-地贫基因突变类型及分布频率见表2。
|
表2 593例α-地贫基因突变类型及其所占的比例［n（%）］ |
||||
|
基因类型 |
检出例数（n） |
所占比例（%） |
||
|
-- SEA/αα |
280 |
47.22 |
||
|
-α3.7/ αα |
110 |
18.55 |
||
|
αCSα/ αα |
81 |
13.66 |
||
|
-α4.2 / αα |
47 |
7.93 |
||
|
αWSα/ αα |
29 |
4.89 |
||
|
--SEA/-α3.7 |
9 |
1.52 |
||
|
--SEA/-α4.2 |
8 |
1.35 |
||
|
-α3.7/-α4.2 |
5 |
0.84 |
||
|
-α3.7/-α3.7 |
4 |
0.67 |
||
|
αQSα/ αα |
4 |
0.67 |
||
|
αCSα/αCSα |
4 |
0.67 |
||
|
--SEA /αCSαα |
4 |
0.67 |
||
|
-α3.7/αWSα |
2 |
0.34 |
||
|
--SEA /αQSα |
1 |
0.17 |
||
|
--SEA /αWSα |
1 |
0.17 |
||
|
-α3.7/αCSα |
1 |
0.17 |
||
|
-α4.2/αWSα |
1 |
0.17 |
||
|
αCSα/αWSα |
1 |
0.17 |
||
|
αα/--THAI |
1 |
0.17 |
||
|
2.3 β-地贫基因突变类型及分布 260例β-地贫基因阳性患者中，检出基因突变类型 13种，β41-42/βN和β17/βN基因类型占所有β-地贫基因阳性患者的88.46%，将近90%，又以β41-42/βN基因类型最多，占50.38%，β-地贫基因突变类型及分布频率见表3。 |
||||
|
基因类型 |
检出例数（n） |
所占比例（%） |
||
|
β41-42/βN |
131 |
50.38 |
||
|
β17/βN |
99 |
38.08 |
||
|
β654/βN |
9 |
3.46 |
||
|
β-28/βN |
7 |
2.69 |
||
|
β71-72/βN |
5 |
1.92 |
||
|
βE/βN |
4 |
1.54 |
||
|
β43/βN |
3 |
1.15 |
||
|
β27-28/βN |
1 |
0.39 |
||
|
βIVS-I-I/βN |
1 |
0.39 |
||
2.4 αβ复合型地贫基因突类型及分布 67例αβ复合型地贫基因阳性患者中，检出基因突变类型 17种，--SEA/β41-42、-α3.7/β41-42、--SEA/β17三个基因类型占所有αβ复合型地贫基因阳性患者的50%左右，又以--SEA/β41-42和-α3.7/β41-42两个基因突变类型最多。αβ复合型地贫基因突类型及分布频率见表4。
|
表4 67例αβ复合型地贫基因突变类型及其所占的比例［n（%）］ |
||
|
基因类型 |
检出例数（n） |
所占比例（%） |
|
--SEA/β41-42 |
12 |
17.91 |
|
-α3.7/β41-42 |
12 |
17.91 |
|
--SEA/β17 |
9 |
13.43 |
|
αCS/β41-42 |
6 |
8.96 |
|
-α3.7/β17 |
5 |
7.46 |
|
αWS/β17 |
4 |
5.96 |
|
-α4.2/β41-42 |
3 |
4.48 |
|
-α4.2/β17 |
3 |
4.48 |
|
αWS/β71-72 |
2 |
2.99 |
|
αWS/β654 |
2 |
2.99 |
|
αCS/β17 |
2 |
2.99 |
|
αQS/β654 |
2 |
2.99 |
|
--SEA/β654 |
1 |
1.49 |
|
-α4.2/β43 |
1 |
1.49 |
|
-α4.2/β71-72 |
1 |
1.49 |
|
αWS/βIVS-1-1 |
1 |
1.49 |
|
αQS/β41-42
| ||
