双胎及三胎妊娠地中海贫血产前基因诊断研究

目的:探讨双胎妊娠和三胎妊娠地中海贫血的产前基因诊断情况。方法:对27例双胎妊娠和三胎妊娠患者进行绒毛膜穿刺或羊膜囊穿刺胎儿取样,采取裂隙聚合酶链反应以及聚合酶链反应结合反向点杂交方法进行产前基因诊断。结果:在进行α地中海贫血产前基因诊断的20例双胎妊娠及1例三胎妊娠中,共对43个胎儿进行取材,共检测出6例Bart's水肿胎,3例血红蛋白H病。在进行β地中海贫血产前基因诊断的6例双胎妊娠中,共对9个胎儿进行取材,共检测到3例中重型β地中海贫血。结论:地中海贫血的多胎妊娠孕妇产前基因诊断能较有效检出Bart's水肿胎和中重型β地中海贫血患儿,可预防重型地中海贫血患儿的出生。     

海南地区地中海贫血产前基因诊断的临床研究

目的:研究检测α-地中海贫血及β-地中海贫血在产前基因诊断中的临床应用价值。方法:对孕妇夫妇携带地中海贫血的48例风险胎儿的羊水(或脐血)应用单管多重PCR体系和反向点杂交法,进行α-地中海贫血和β-地中海贫血基因诊断。结果:共检测出地中海贫血胎儿38例。其中α-地中海贫血14例,包括东南亚缺失型杂合子(--SEA/αα)2例,东南亚缺失型纯合子(--SEA/--SEA)8例,左缺失型杂合子(-α4.2/αα)1例,右缺失型杂合子(-α3.7/αα)2例,非缺失型点突变(ααT/αα)1例;β-地中海贫血24例,包括CD41-42杂合子16例,CD41-42纯合子2例,-28(A-G)杂合子3例,双重杂合子(IVS2nt654/CD41-42,-28(A-G)/CD71-72(+A),CD41-42/-α3.7)3例。其中10例重型地贫儿引产,1例重型地贫儿产后新生儿死亡,其余均足月分娩存活。所有病例经引产或正常分娩后留取脐带血,作地贫基因诊断,与产前诊断结果一致。结论:应用单管多重PCR体系及反向点杂交法能快速、准确进行α-和β-地中海贫血产前基因检测,这对于有效预防重型地中海贫血胎儿出生具有重大临床意义。     

深圳市孕妇地中海贫血产前筛查及产前诊断

目的：调查深圳市孕妇地中海贫血发病率、基因突变类型，对高风险胎儿进行产前诊断。方法：1998年1月至2002年12月采用二步法对产前检查的4136例孕妇进行地中海贫血筛查。结果：检出地中海贫血阳性病例297例，发病率7．18％，其中。地中海贫血阳性病例172例，发病率4．16％；β地中海贫血阳性病例125例，发病率3．02％。229例被确定了基因型。对19对夫妇均为地中海贫血携带者胎儿进行产前基因诊断，确定正常胎儿3例，α1地中海贫血杂合子4例，β地中海贫血杂合子8例，Bart‘S水肿胎儿2例，β地中海贫血双重杂合子2例。结论：通过产前筛查地中海贫血，确诊重症患儿及时终止妊娠，可有效地避免重症患儿的出生。     

应用PCR-RDB技术对β地中海贫血进行快速产前基因诊断

目的　为了降低 β地中海贫血重症患儿的出生率 ,达到优生的目的。　方法　对 5 2 7对孕妇及其配偶进行血液学筛查 ,用 PCR- RDB法对夫妇双方均为 β地中海贫血携带者的孕期夫妇进行产前基因诊断 ,并取脐血验证结果。　结果　共筛出 β地中海贫血阳性患者 2 8例 ,轻型 β地中海贫血阳性率为 2 .6 6 %。男女阳性率为 1∶ 1.15 ,4例产前基因诊断中 ,确定正常胎儿 1例 ,重症胎儿 3例(纯合子 1例 ,双重杂合子 2例 ) ,重型 β地中海贫血胎儿于诊断后两周内终止妊娠。　结论　 PCR-RDB技术可有效减少 β地中海贫血重症患儿的出生 ,具有重要的优生学意义。     

α和β地中海贫血双重杂合子的基因诊断

目的 :探讨α和β地中海贫血双重杂合子的基因诊断。方法 :采用跨越缺失区断裂点的PCR方法检测α 地中海贫血 1基因。采用等位基因特异寡核苷酸探针 /反向点杂交 (ASO/RDB)技术检测 β 地中海贫血基因。 结果 :对地中海贫血筛查中发现的 3例疑为α和β地中海贫血双重杂合子进行基因诊断 ,均属于东南亚缺失型α 地中海贫血 1和β 地中海贫血双重杂合子 ,其中 1例为α 地中海贫血 1和β 2 8(A→G) ,1例为α 地中海贫血 1和βIVS Ⅱ 6 5 4 (C→T) ,1例为α 地中海贫血 1和HbE。结论 :α和 β地中海贫血双重杂合子的检出对临床准确进行地中海贫血的产前诊断有重要意义。     

贵阳地区孕期夫妇β-地中海贫血血液学筛查及基因突变分析的研究

目的：为丰富人类基因组多样性研究和疾病分析研究的内容，对贵阳地区进行大样本孕期夫妇β－地中海贫血筛查及基因突变的分析。方法：采用红细胞渗透休克试验和血红蛋白F（HbF）及血红蛋白A2（HbA2）定量测定，对孕期夫妇进行β－地中海贫血血液学筛查，阳性者采用PCR－RDB法进行基因突变分析。结果：在受检的1054例中，共检出β－地中海贫血携带者28例，发生率为2．66％。结论：通过对贵阳地区孕期夫妇进行的β－地中海贫血调查，基因分析，为今后对该地区人群进行生育指导，产前基因诊断，提高人口素质具有重要意义。     

应用扩增不应突变系统技术对β-地中海贫血行快速产前基因诊断

β地中海贫血是我国南方常见的常染色体隐性遗传性疾病。目前常用聚合酶链反应(ＰＣＲ)检测基因已知点突变的方法进行产前诊断。而对β地中海贫血进行基因诊断最有效的方法主要有反向点杂交法[1]和扩增不应突变系统(ａｍｐｌｉｆｉｃａｔｉｏｎｒｅｆｒａｃｔｏｒｙｍｕｔａｔｉｏｎｓｙｓｔｅｍ,ＡＲＭＳ)技术[2]。我们应用ＡＲＭＳ技术完成了1例有β地中海贫血的快速产前基因诊断,现报道如下。一、资料与方法1.资料:患者因第1胎生育β地中海贫血患儿,现又妊娠第2胎而来我室遗传咨询门诊就诊,要求产前诊断。第1胎曾在湖南医科大学附属湘雅…     

福建地区孕妇α地中海贫血基因突变类型及产前诊断

目的:了解福建地区孕妇α地中海贫血的基因突变类型及其分布特征,对高风险胎儿进行产前诊断。方法:应用聚合酶链反应(PCR)和反向斑点杂交(RDB)技术,进行α地中海贫血基因分析和产前诊断;对少见的泰国缺失型α地中海贫血基因类型进行测序确认。结果:1502例孕妇中检出314例α地中海贫血患者,阳性率为20.9%,其中东南亚缺失型杂合子(--SEA/αα)225例,右缺失型杂合子(-α3.7/αα)30例,左缺失型杂合子(-α4.2/αα)10例,左缺失型纯合子(-α4.2/-α4.2)1例,右缺失型纯合子(-α3.7/-α3.7)1例,血红蛋白H病27例(-α3.7/--SEA9例,-α4.2/--SEA13例,ααCS/--SEA2例,ααQS/--SEA2例,ααWS/--SEA1例),另外检出少见泰国缺失型α地中海贫血4例;非缺失型α地中海贫血中,ααQS/αα8例,ααCS/αα6例,ααWS/αα2例。对28对夫妇均为地中海贫血携带者胎儿进行了产前基因诊断,确定正常胎儿6例,地中海贫血杂合子9例,巴氏水肿胎儿(HbBart's)13例。结论:福建地区α地中海贫血基因突变类型较为复杂,首次报道福建地区非缺...     

胚外体腔穿刺术应用于α地中海盆血产前诊断的探讨

目的：探讨胚外体腔穿刺术应用于α地中海贫血产前诊断的可行性。方法：对50例妊娠6－10周、要求人工流产的单胎妊娠孕妇在终止妊娠前行胚外体腔穿刺术抽吸胚外体腔液，吸宫术后取绒毛，采用聚合酶链反应（PCR）扩增胚外体腔细胞及绒毛的α地中海贫血基因，比较两种标本诊断的符合率。结果：40例胚外体腔细胞成功地扩增α地中海贫血基因，结果均与绒毛相符。结论：通过胚外体腔穿刺术取胚外体腔细胞行PCR检测可用于α地中海贫血的早期产前诊断，但应进一步提高诊断方法的敏感性。     

应用突变引物延伸扩增技术快速前产诊断β地中海贫血基？…

目的 探讨综合应用突变引物延伸扩增（ＭＯＥＡ）及巢式聚合酶链反应（ＰＣＲ）技术进行β地中海贫血产前诊断的可行性。方法 行钐一对外侧引的扩增１．５Ｋｂβ株收 用ＭＯＥＡ技术检测β地中海贫血点突变。结果 完成了６例β地中海贫血高危胎儿的产前基因诊断,其中双重杂合子１例,杂合子３例,正常胎儿２例;经分娩或流产后基因分析验证,结果与产前诊断完全一致。结论ＭＯＥＡ技术适合于已知点突变的基因诊断和产前诊断,具     

Invasive prenatal diagnosis of α-thalassemia to control Hb Bart’s hydrops fetalis syndrome: 15 years of experience

Purpose

The aim of the present study was to report experiences with invasive prenatal diagnosis of α-thalassemia for the prevention of Hb Bart’s hydrops fetalis syndrome in the Guangxi Zhuang Autonomous Region, China.

Methods

Pregnant women and their partners who tested positive for α⁰-thalassemia or were diagnosed with HbH diseases were counseled and suggested to undergo a prenatal diagnostic procedure for α-thalassemia. Fetal material was obtained by chorionic villus sampling (CVS) between 9 and 13 weeks of gestation, by amniocentesis between 16 and 24 weeks of gestation and by cordocentesis after 24 weeks of gestation. The α⁰-thalassemia gene types were detected by gap polymerase chain reaction (Gap-PCR). All results were finally confirmed by DNA analysis after delivery or termination of pregnancy.

Results

An invasive prenatal α-thalassemia diagnosis was performed in 3155 cases at risk for Hb Bart’s hydrops fetalis syndrome at our hospital from 2002 to 2016. CVS was performed in 1559 cases (49.4%), amniocentesis in 1240 cases (39.3%) and cordocentesis in 356 cases (11.3%). In total, 786 fetuses were diagnosed as Hb Bart’s hydrops fetalis syndrome. Among these cases, the α-thalassemia genotype was --^SEA/--^SEA in 784 cases and --^SEA/--^THAI in 2 cases. All affected pregnancies were terminated in time.

Conclusions

This extensive experience suggests that carrier screening, molecular diagnostics, genetic counselling, and prenatal diagnosis are effective measures to prevent Hb Bart’s hydrops fetalis syndrome.

     

Prenatal diagnosis of β-thalassemia in Guangxi Zhuang Autonomous Region, China

Purpose

The aim of this study was to establish a comprehensive prenatal diagnosis service and to control the birth of thalassemia children in Guangxi Zhuang Automonous Region, China.

Methods

Prenatal diagnosis was performed in 1,058 couples with ‘at risk’ β-thalassemia from Guangxi Zhuang Automonous Region. Fetal samplings were collected by chorionic villus sampling in the first trimester, by amniocentesis in the second trimester and by cordocentesis in the third trimester. DNA analysis was carried out using polymerase chain reaction, reverse dot blot assay, multiplex ligation-dependent probe amplification method and DNA sequencing. Automated high-performance liquid chromatography system was used to analyze the fetal hemoglobin in pregnancies in case mutations were unidentified.

Results

A total of 12 different β-thalassemia mutations were characterized from 2,116 parents. The most common mutation for β-thalassemia was CD41–42 (-CTTT) followed by CD17 (A→T). Prenatal testing revealed 315 normal fetuses, 500 carriers and 253 β-thalassemia major fetuses. The couples having fetuses with β-thalassemia major were counselled to terminate the pregnancies. Postnatal follow-up confirmed all pregnancies.

Conclusion

Our prenatal diagnosis strategy proved to be highly effective in reducing severe thalassemia in pregnant populations.     

Second trimester maternal serum markers and a predictive model for predicting fetal hemoglobin Bart’s disease

Objective: To compare the levels of maternal serum α-fetoprotein (AFP), unconjugated estriol (uE3) and free β-human chorionic gonadotropin (free β-hCG) between pregnancies with fetal Hb Bart’s disease and unaffected pregnancies. Methods: 148 pregnancies at risk of fetal Hb Bart’s disease scheduled for cordocentesis at 18 to 22 weeks were prospectively recruited into the study. AFP, uE3 and free β-hCG concentrations were measured before cordocentesis and the final fetal diagnosis of Hb Bart’s disease was based on fetal Hb typing using high-performance liquid chromatography. Results: AFP and free β-hCG were significantly higher whereas uE3 was lower in women with fetal Hb Bart’s disease than those with unaffected fetuses (1.94 MoM, 1.38 MoM and 0.81 MoM respectively). Hb Bart’s predictive model; probability = 1/1+e^{?[2.876 + 1.333(AFP) ? 6.310(uE3)]}, effectively predicted fetal Hb Bart’s disease (AUC ROC 0.91, 95% CI 0.84–0.97) with 61.5% sensitivity and 98.1% specificity using a cut-off probability at greater than 0.5. Conclusions: In triple test, serum AFP and hCG levels are significantly higher while serum uE3 is significantly lower in pregnancies with fetal Hb Bart’s disease. Hb Bart’s predictive model included AFP and uE3 is relatively effective and may be helpful in Hb Bart’s prenatal screening.     

Two cases of non-haematological cause of fetal hydrops in at-risk pregnancies for homozygous α0-thalassemia

In recent years, sonography has been successfully used as an alternative method for prenatal detection of Hb Bart's disease in areas with high prevalence of α-thalassemia. We present two cases in which the fetuses demonstrated signs of Hb Bart's disease by sonography, however, invasive procedures could not confirm it. We recommend that, in prenatal diagnosis of Hb Bart's disease by sonography, the diagnosis should always be confirmed with definitive methods to exclude false-positive findings.     

Prenatal control of Hb Bart’s hydrops fetalis: a two-year experience at a mainland Chinese hospital

α-Thalassemia is a common inherited disease in southern China. The severest form is Hb Bart’s hydrops fetalis, in which the affected fetuses almost always die in utero or shortly after birth, and the mothers are at high risk for severe morbidity. Therefore, this condition should be controlled, especially prenatally. In this study, we reported on a two-year experience in prenatal control of Hb Bart’s hydrops fetalis at a mainland Chinese hospital. Totally, 573 pregnancies at risk for Hb Bart’s hydrops fetalis were referred and different prenatal procedures were offered depending on the gestational age at presentation. One hundred fifty-two affected fetuses were diagnosed prenatally; among these, only half presented in early gestation, and were terminated in time. Although our prenatal program has successfully prevented the birth of children with severe thalassemia, it does not show a satisfactory outcome, considering the gestational age when an affected pregnancy is terminated.     

2种新的中国人β-地中海贫血基因突变类型CD13/14(-C)和beta nt1582(A>G)突变

目的:报道2种新的中国人β-地中海贫血(β-thalassemias,β-地贫)基因突变类型CD13/14(-C)和beta nt1582(A>G)突变。方法:疑似β-地贫患者10例,其中7例为临床疑似轻型β-地贫基因携带者,1例为临床疑似重型β-地贫患者,2例为父母双方均为β-地贫基因携带者的胎儿。应用聚合酶链反应联合反向点杂交技术(PCR-RDB),以及基于PCR技术的DNA测序技术检测β血红蛋白基因。根据患者表型和以往文献报道,对新发现的基因突变性质进行分析。结果:检测出2种β-地贫常见基因突变型,分别是IVS-2-654(C>T)和-28(A>G)。检测出5种β-地贫稀有基因突变型,分别是beta nt1582(A>G),PolyA(AATAAA>GATAAA);CD13/14(-C);beta nt1586(A>G),PolyA(AATAAA>AATAGA);IVS-1-1(G>T);IVS-2-2(-T);其中前2种为新发现的β-地贫基因突变类型。结论:发现了2种新的β-地贫基因突变类型,其表型效果可能为β0或β+。对常规基因检测技术不能诊断的β-地贫疑似病例,可作DNA测序进行确诊。     

降低出生缺陷关键技术及干预措施的研究

目的：探讨降低出生缺陷的关键技术及干预措施。方法以Duchenne进行性肌营养不良(DMD)、脊肌萎缩症(SMA)、地中海贫血（地贫）、葡萄糖-6-磷酸脱氢酶缺乏症(G6PD)、唐氏综合征(DS)、18三体综合征(ES)、神经管缺陷(NTD)等为目标疾病,调查2007年1月至2009年12月昆明市盘龙区、五华区共5004例孕妇补充叶酸的情况;对云南省第一人民医院、第二人民医院、云南省曲靖市第一人民医院、第二人民医院、曲靖市妇幼医院、云南省临沧市人民医院、昆明玛利亚女子医院、昆明市盘龙区妇幼保健所、云南省大理市妇幼保健院进行产前检查的27 660例孕妇,在孕8～20周+6进行血清学筛查;对筛查高风险或有其他产前诊断指征的孕妇,经遗传咨询后进行细胞遗传学产前诊断和胎儿超声检查;对有DMD、SMA、地贫、G6PD患儿生育史或家族史的孕妇,用相应的DNA分析技术进行产前基因诊断;随访妊娠结局后评价干预效果。结果5004例孕妇中围孕期补充叶酸者占30.10％ (1506/5004);接受血清学筛查的27 660例孕妇中发现DS、ES、NTD高风险孕妇2313例,其中2096例孕妇自愿接受细胞遗传学产前诊断（其中2例为双胎）;另有67例DMD、SMA、地贫、G6PD高风险的孕妇通过遗传咨询自愿接受产前基因诊断。对以上2163例高风险孕妇（共2165例胎儿）进行产前诊断,确诊染色体异常胎儿102例、NTD17例、DMD 4例,重型α地贫l例;经遗传咨询后自愿终止妊娠91例严重出生缺陷胎儿,另有l例双胎之一为DS于孕24周胎死宫内,32例染色体平衡易位或倒位胎儿继续妊娠。接受产前诊断的2163例孕妇足月分娩新生儿2071例,羊膜腔穿刺术后l周内流产2例（胎儿染色体均正常）;有4例血清学筛查高风险孕妇因拒绝接受产前诊断而生育了4例DS患儿。随机抽样随访5000例血清学筛查低风险孕妇的妊娠结局,未发现活产儿中有上述目标疾病的患儿。血清学筛查对DS的检出率为84％( 27/32),假阳性率为6.153％( 1702/27 660)。结论孕前及孕早期补充叶酸可降低出生缺陷风险,但育龄期妇女主动补充叶酸者仅占1/3;血清学筛查可高效检出DS、ES和NTD;遗传咨询对诊断高风险和遗传病家族史的人群至关重要;以血清学筛查和产前诊断为关键技术,与常规产前检查相结合,可以降低严重出生缺陷的发生率,应成为我国的新型围产保健策略。     

52例先天性心脏病胎儿产前诊断及临床分析

目的通过心脏畸形胎儿产前诊断及临床预后评分评估为先天性心脏病胎儿遗传咨询及临床分析提供更多依据。方法收集2018年4月至2019年10月因胎儿心脏畸形来怀化市妇幼保健院产前诊断中心就诊的52例孕妇临床资料。通过产前诊断获得标本并行染色体核型及CMA检测。结果52例心脏畸形胎儿中染色体核型异常为13.46%(7/52),核型正常的胎儿中有5例检出拷贝数变异(copy number variation,CNV),检出率为9.6%(5/52)。40例染色体核型及微阵列分析均正常的胎儿中,按出生缺陷临床预后评分体系评分。其中0分Ⅰ级正常变异9例,均继续妊娠;1~3分Ⅱ级者共17例,继续妊娠16例;4~6分Ⅲ级者共11例,继续妊娠3例;7~9分Ⅳ级者3例,均引产。40例中继续妊娠28例。结论胎儿先天性心脏病与遗传因素相关,需行产前诊断,排除遗传因素后行临床预后评分评估,对临床分析及围产期管理,改善胎儿预后,提高我国出生人口质量起到重要的作用。     

Antenatal Screening for Identification of Couples for Prenatal Diagnosis of Severe Hemoglobinopathies in Surat, South Gujarat

Purpose

Our aim was to identify couples at risk of having a homozygous or compound heterozygous child with a severe hemoglobinopathy by antenatal screening and prenatal diagnosis in Surat, South Gujarat.

Method

Pregnant women were screened for hemoglobinopathies by means of red cell indices, the solubility test, cellulose acetate electrophoresis tests, and confirmation by HPLC. Husbands of the pregnant women having hemoglobinopathies were counseled and screened for hemoglobinopathies. The couples at risk were again counseled and referred to the National Institute of Immunohematology, where mutations in parents and fetuses were identified by molecular analysis. After prenatal diagnosis, the continuing pregnancies were followed up and infants were tested at birth.

Results

Out of 3,009 women, 37.04, 52.6, and 10.3 % were in the first, second, and third trimester of pregnancy, respectively. Among those having hemoglobinopathies, 102 (3.38 %) had the β-thalassemia trait, 46 (1.5 %) the Sickle cell trait, and 26 (0.86) had hemoglobin variants like Hb D_Punjab, Hb E, Hb D_Iran, Hb Q_India, Hb J_Paris-I, and Hb O_Indonesia. Out of the 14 couples at risk of having an affected child, 11 (78.5 %) couples opted for prenatal diagnosis. Three fetuses had homozygous β-thalassemia and hence the pregnancies were terminated. Follow up of normal or heterozygous fetuses confirmed the diagnosis.

Conclusion

During antenatal screening, we found many Hb variants of β and α globin chains. Late antenatal registration, non-cooperation of the husband for investigation, and refusal for prenatal diagnosis are the main hurdles in the hemoglobinopathy prevention program and awareness is necessary.