妊娠中期唐氏综合征和神经管缺损的产前筛查和产前诊断的研究

目的对重庆地区妊娠中期的妇女进行唐氏综合征和其他先天畸形的产前筛查,诊断,以降低出生缺陷。方法对13017例14~20周的孕妇采用酶联免疫方法检测孕妇血中的AFP和β-HCG浓度,通过计算机软件计算危险系数（唐筛风险值≥275,神经管缺损AFP≥2.5 MoMs）。对唐氏高危的孕妇取羊水做染色体和基因诊断,神经管缺损高危者行超声波检查。结果13017孕妇中筛查出唐氏综合征,神经管缺损,18,13三体高危771例,占5.92%。唐氏高危607例,占4.66%。有352例愿意进一步确诊,发现11例异常妊娠。116例神经管缺损高危（占0.89%）中全部做超声检查。发现3例神经管缺损的胎儿。48例18,13三体高危中5例做羊水染色体为正常,其余虽未做进一步确诊,但有3例胎死宫内,证明也有异常妊娠。结论唐氏综合征和神经管缺陷的产前筛查并结合其他方法进行诊断。对降低出生缺陷有积极的意义。     

Second trimester prenatal diagnosis of the fragile X

The fra(X) chromosome was detected in 5 samples of amniotic fluid cells in a series of 23 pregnancies at risk. The prenatal results were confirmed in 2 male abortuses, one with a relatively high and one with a very low frequency of expression in both amniocytes and fetal tissue. In a third male fetus with low expression in amniocytes, the fra(X) was not detected in the fetal tissues tested. In another male with low expression in amniocytes the fra(X) was not detected after birth. In one female with a low expression in amniocytes, a very high frequency (28%) was detected in cord blood after birth. Low expression of the fra(X) was found in a 4-year-old normally developed girl, where the prenatal results had been negative. In 4 males and 4 females the negative prenatal diagnoses were confirmed after birth. This study indicates that prenatal diagnosis of the fragile X after amniocentesis may be complicated, either due to technical problems related to the use of amniotic fluid cells, or due to genetic heterogeneity, or both. Part of this heterogeneity could be due to the existence of normal male transmitters. Also, it seems that the frequency of expression in amniocytes from female carriers can not be used for the prediction of the frequency in blood after birth.     

孕早期Down''''s综合征的产前筛查及产前诊断研究

目的探讨孕早期孕早期Down's综合征的产前筛查及产前诊断方案.方法时间分辨荧光免疫法(TRFIA)对孕8-13w的5,433例孕妇血清中的β-hCG、PAPP-A2种血清标记物进行检测,筛查出8例DS胎儿(通过绒毛染色体核型分析和STR-PCR分析明确诊断);比较分析8例DS胎儿母血清与184例对照病例血清中两种标记物水平.结果DS组母血中β-hCG、PAPP-A水平均值分别为2.31MoM和0.42MoM,与对照组差别有显著性意义(P＜0.05);β-hCG、PAPP-A两项指标联合筛查,DS的阳性检出率为75%,假阳性率为8.35%;有7例DS胎儿经绒毛染色体核型分析确诊,3例DS胎儿经PCR-STR分析确诊.结论孕早期β-hCG、PAPP-A两联标记物筛查DS可以达到孕中期三联标记物筛查效果;细胞遗传学与分子遗传学相结合可以提高产前诊断的成功率和准确性.     

Characterization of first trimester fetal erythroblasts for non-invasive prenatal diagnosis

Isolating fetal erythroblasts from first trimester maternal blood offers a promising non-invasive alternative for prenatal diagnosis. The aim of this study was to characterize the biological properties of first trimester primitive erythroblasts to facilitate their enrichment from first trimester maternal blood. Primitive erythroblasts were the predominant cell type until 12 weeks gestation, after which time their numbers declined steeply; 100% were epsilon-globin-positive versus <0.06% definitive erythroblasts. Buoyant densities of first trimester fetal erythroblasts ranged from 1.077 to 1.130 g/ml, and optimal recoveries were obtained with Percoll 1118. Although primitive erythroblasts carried a negative surface charge and were resistant to NH(4)Cl lysis, these properties had only a limited role in fetal cell enrichment. Immunophenotyping showed that primitive, like definitive, erythroblasts were GPA+, CD47+, CD45- and CD35-, whereas CD71 expression was weak/undetectable on primitive erythroblasts but strongly positive on 100% of definitive erythroblasts; primitive erythroblasts were also CD36- whereas definitive erythroblasts were CD36+. We therefore used CD45/GPA selection of Percoll 1118-separated cells to demonstrate successful enrichment of male epsilon-globin-positive fetal erythroblasts from model mixtures, and as proof of principle from some first trimester maternal blood samples. Fetal cell enrichment protocols based on first trimester epsilon-globin-positive primitive erythroblasts may allow reliable enrichment of fetal cells from maternal blood for early non-invasive prenatal diagnosis of genetic disorders.     

First trimester prenatal diagnosis using transcervical cells: an evaluation

Human trophoblastic cells can be retrieved by minimally invasiveprocedures from the endocervical canal between 6 and 15 weeksgestation. The incidence with which fetal cells can be detectedin transcervical cell (TCC) samples varies according to themethod of collection and the molecular techniques employed fortheir identification. Fluorescence in-situ hybridization (FISH)and polymerase chain reaction (PCR) assays have been successfullyused to detect aneuploidies and Y-derived DNA sequences in TCCsamples obtained from male fetuses. Chromosome specific polymorphicDNA sequences (small tandem repeats) have also been employedto identify, by quantitative fluorescent PCR, fetal cells inTCC samples. Furthermore, Rh(D) sequences have been amplifiedin samples retrieved from Rh(D) negative mothers. Preliminaryresults also suggest that prenatal diagnoses of thalassaemiaand sickle cell anaemia can be performed on clumps of cellsisolated from TCC samples. Overall systematic studies allowoptimism about the possibility of using TCC samples for theprenatal diagnosis of selected inherited disorders.     

First trimester prenatal diagnosis of Menkes disease by DNA analysis.

Menkes disease is an X linked recessive disorder of copper metabolism characterised by neurological symptoms and connective tissue manifestations. The defective gene in Menkes disease has recently been isolated and the gene product is predicted to be a copper transporting ATPase. The diagnosis of Menkes disease has hitherto been performed by biochemical analysis, based on intracellular accumulation of copper. Cloning the gene opened up the possibility of establishing precise and reliable carrier and prenatal diagnosis by defining the molecular defect. In this report we describe the partial deletion of the Menkes gene in a patient who had inherited the mutation from his phenotypically normal mother. This information enabled us to perform prenatal diagnosis by direct mutation analysis of the mother's sixth pregnancy and we detected the same deletion, indicating that the male fetus was affected. This first prenatal diagnosis of Menkes disease by direct mutation analysis shows some advantages of DNA analysis compared to biochemical diagnosis.     

产前诊断中染色体倒位与胎儿表型效应的关系

目的探讨胎儿染色体倒位的表型效应。方法回顾性分析147例产前诊断为染色体倒位的胎儿的细胞遗传学特点和超声波检查结果。结果 7108例产前诊断的孕妇检出胎儿染色体倒位147例,检出率为2.1%,其中超声征象异常检出率为7.5%(11/147)例。134例(91.2%)为父母遗传的倒位,超声征象异常检出率为1.5%(2/134);13例(8.8%)为新发性倒位,超声征象异常检出率为69.2%(9/13)。新发性倒位胎儿的超声征象异常检出率高于遗传性倒位(P<0.05)。常染色体倒位占82.3%(121/147),超声征象异常检出率为5.0%(6/121);性染色体倒位占17.7%(26/147),超声征象异常检出率为19.2%(5/26)。性染色体倒位产前超声征象异常检出率较常染色体倒位的高(P<0.05)。结论胎儿染色体倒位的表型效应评估可参考产前超声征象是否异常、倒位的染色体是遗传性或新发性、是遗传自表型正常或异常的双亲、倒位染色体的类型。     

Calcium homeostasis in second trimester fetuses.

The concentrations of ionised calcium ions (Ca++), total calcium, parathyroid hormone, pH, total protein, albumin, sodium, and potassium were measured in paired fetal and maternal blood from pregnancies at 15 to 24 weeks' gestation. Pure fetal blood samples were obtained fetoscopically. The concentrations of fetal ionised calcium ions (n = 26); mean (SD) 1.33 (0.12) mmol/l (5.32 (0.48) mg/100 ml) and those of parathyroid hormone (n = 9); 68 (19) pmol/l (58 (16) micrograms/100 ml) were significantly higher than those of the mothers: 1.18 (0.09) mmol/l (4.7 (0.4) mg/100 ml), and 40 pmol/l (less than 34 micrograms/100 ml), respectively. There was no difference between measured fetal and maternal total calcium, pH, and electrolytes. The fetal total protein and albumin concentrations increased with gestation but were always lower than the equivalent maternal values. The calculated total calcium was 0.23-0.45 mmol/l (0.9-1.8 mg/100 ml) higher in the fetal than in maternal blood from the same pregnancy. There were no fetal arteriovenous differences in ionised calcium ions despite higher venous pH.     

Meckel syndrome and the prenatal diagnosis of neural tube defects.

Two fetuses, terminated after prenatal diagnosis of aneural tube defect, had Meckel syndrome. There have now been three fetuses with this syndrome in a series of 35 terminated because of open lesions of the neural tube. It is suggested that such therapeutically aborted fetuses represent a highly selected group, among which a rare condition like Meckel syndrome will be concentrated. The need for a detailed examination of all terminated fetuses is emphasised, for the identification of such an autosomal recessive condition alters the genetic counselling for a future pregnancy.     

First trimester prenatal diagnosis of haemophilia a using factor VIII gene probe

Accurate first-trimester prenatal diagnosis was achieved in a Japanese haemophilia A family by the use of a restriction fragment length polymorphism (RFLP) located within the F.VIII gene. Since the pregnant woman's heterozygosity forBclI polymorphism in F.VIII/intron 18 (F8A) probe was informative, chorionic villus sampling (CVS) was performed at 9 weeks of gestation. Restriction analysis showed that the fetus was heterozygous for theBclI site and had received a normal paternal X chromosome (0.9 kb) and a normal maternal X (1.2 kb). Therefore, we concluded that the fetus was a non-carrier female. Pregnancy went to term and woman gave birth to an apparently healthy female. At one week after birth a coagulation study confirmed that the newborn infant is not a carrier. The first-trimester prenatal diagnosis of haemophilia A is possible by CVS due to a RFLP in the F.VIII gene.     

First trimester prenatal diagnosis of haemophilia A using factor VIII gene probe

Accurate first-trimester prenatal diagnosis was achieved in a Japanese haemophilia A family by the use of a restriction fragment length polymorphism (RFLP) located within the F.VIII gene. Since the pregnant woman's heterozygosity for BclI polymorphism in F.VIII/intron 18 (F8A) probe was informative, chorionic villus sampling (CVS) was performed at 9 weeks of gestation. Restriction analysis showed that the fetus was heterozygous for the BclI site and had received a normal paternal X chromosome (0.9 kb) and a normal maternal X (1.2 kb). Therefore, we concluded that the fetus was a non-carrier female. Pregnancy went to term and woman gave birth to an apparently healthy female. At one week after birth a coagulation study confirmed that the newborn infant is not a carrier. The first-trimester prenatal diagnosis of haemophilia A is possible by CVS due to a RFLP in the F.VIII gene.     

用高效液相色谱技术产前快速诊断β-地中海贫血

目的探讨应用高效液相色谱技术(HPLC)在孕中期快速产前诊断β-地中海贫血(β-地贫)的可行性。方法夫妇双方均为β-地贫基因携带者的孕妇73例,在妊娠19~31w通过经母腹脐静脉穿刺的方法抽取胎血。胎血血红蛋白(Hb)各组分比例的测定采用HPLC,胎血β-地贫基因的检测采用PCR-反向点杂交的方法。结果HPLC检出18例胎血只有HbF而无HbA,PCR-RDB证实此18例胎儿基因型均为β-地贫基因突变纯合子或双重杂合子。剩余55例胎血都有不等量的HbA,其中4例HbA值为0.5%~0.7%,均为带有-28基因突变的双重杂合子;51例HbA值范围1.4%~10.4%,其中30例为β-地贫基因突变杂合子,21例基因型正常。结论对于重型β-地贫,用HPLC测定胎血HbA值和胎儿基因型分析进行产前诊断有很好的相符性。HPLC用在孕中期可以作为产前快速诊断重型β-地贫的一种方法。     

PTPN11 analysis for the prenatal diagnosis of Noonan syndrome in fetuses with abnormal ultrasound findings

Noonan syndrome (NS) is an autosomal dominant disorder characterized by short stature, congenital heart defects and distinctive facies. The disorder is genetically heterogeneous with approximately 50% of patients having PTPN11 mutations. Prenatally, the diagnosis of NS has been suspected following certain ultrasound findings, such as cystic hygroma, increased nuchal translucency (NT) and hydrops fetalis. Studies of fetuses with cystic hygroma have suggested an NS prevalence of 1–3%. A retrospective review was performed to assess the utility of PTPN11 testing based on prenatal sonographic findings ( n = 134). The most commonly reported indications for testing were increased NT and cystic hygroma. Analysis showed heterozygous missense mutations in 12 fetuses, corresponding to a positive test rate of 9%. PTPN11 mutations were identified in 16% and 2% of fetuses with cystic hygroma and increased NT, respectively. Among fetuses with isolated cystic hygroma, PTPN11 mutation prevalence was 11%. The mutations observed in the three fetuses with hydrops fetalis had previously been reported as somatic cancer mutations. Prenatal PTPN11 testing has diagnostic and possible prognostic properties that can aid in risk assessment and genetic counseling. As NS is genetically heterogeneous, negative PTPN11 testing cannot exclude the diagnosis and further study is warranted regarding the other NS genes.     

Ultrasonic diagnosis of malformations during the 1st trimester of pregnancy]

Available are the results of ultrasonic investigations for 11 women with embryonal anomalies in the I pregnancy trimester. Echography was demonstrated to detect gross CNS malformations (anencephaly, exencephaly), lymphangiomas, omphalocele, conjoined twins, acardia of amorphic embryo, etc. Transvaginal sensors proved highly informative.