植入前遗传学诊断的研究进展

植入前遗传学诊断是对体外受精的胚胎进行遗传学诊断，将正常的胚胎植入子宫，其技术主要包括胚胎活检、聚合酶链反应及荧光原位杂交。现将这些技术在植入前遗传学诊断中的应用及所存在的相关问题进行综述。     

植入前遗传学诊断的新进展

植入前遗传学诊断作为产前诊断的一种形式，可在胎种植前进行诊断，从而防止遗传病的发生。其技术主要包括胚胎活检、聚合酶链反应及荧光原位杂交。现就这些技术在植入前遗传学诊断中的应用、存在的问题、解决及改进的方法进行综述。     

FISH技术在胚胎植入前遗传学诊断中的应用及前景

随着体外受精-胚胎移植技术的快速发展和进步，以及单细胞水平上基因诊断技术的成功，使得在体外受精过程中，胚胎移植入母体子宫前进行遗传学诊断成为可能。本文综述荧光原位杂交（FISH）技术在胚胎植入前遗传学诊断（PGD）中的应用和研究进展。     

染色体易位携带者的胚胎植入前遗传学诊断研究进展

染色体易位是常见的染色体结构异常。应用荧光原位杂交技术，染色体易位携带者可在胚胎植入前遗传学诊断的帮助下增加正常妊娠的机会。现就相互易位减数分裂的情况进行综述，并讨论应用荧光原位杂交技术对染色体易位携带者进行胚胎植入前遗传学诊断的策略。     

染色体病在胚胎植入前遗传学诊断中的研究与发展

随着辅助生殖技术的发展,越来越多的不孕患者通过这项高科技技术得到了自己的后代,但临床发现一部分患者在进行数次辅助生殖助孕后,仍然无法受孕;有的患者即使具有良好的内膜容受性及形态优质的胚胎仍然会发生反复流产.上世纪80年代末,植入前遗传学诊断的出现,使人们认识到这些问题很可能与胚胎染色体异常有关,并运用于临床,大大提高了IVF的植入率及临床妊娠率,使具有遗传缺陷的夫妇能生育健康的后代.因此,本文从分子细胞遗传学角度综述导致植入前胚胎染色体异常的机理与影响因素,荧光原位杂交技术在植入前胚胎染色体异常检测中发挥的作用,以及植入前遗传学诊断在染色体异常方面的研究进展,及其对辅助生殖技术的影响.     

跨断裂点探针及其在胚胎植入前遗传学诊断研究进展

植入前遗传学诊断(preimplantation genetic diagnosis,PGD)是产前诊断的一种新方案,理论上可避免以往产前诊断有异常而不得不终止妊娠的遗憾。染色体异常是PGD的很重要一部分,其中的染色体结构异常是。PGD的难点之一。用目前商业化的探针不能区分正常和平衡易位的核型,针对各个病例的跨断裂点探针能区分这两种核型。本文就跨断裂点探针的技术路线、应用实例及其应用前景作一简要介绍。     

植入前遗传学诊断中卵裂球固定技术改进

目的改进植入前遗传学诊断卵裂球固定技术,减少卵裂球细胞丢失,获得更好的固定效率、更高的荧光原位杂交成功率,简化操作程序.方法体外授精治疗周期废弃胚胎的96个卵裂球细胞,分别用3种不同的固定技术进行固定,固定后使用X、Y着丝粒探针进行荧光原位杂交,比较其固定效率和杂交效率.结果改进方法固定率和杂交率均为100%.而两种传统技术的固定率分别为90%,83.3%;杂交率为80%,73.3%.结论这种新的固定卵裂球技术从根本上消除了卵裂球标本的丢失,使PGD结果更为可靠;同时简化了操作程序,值得推广.     

单基因遗传病的植入前遗传学诊断研究进展

近十多年来，单基因遗传病的植入前遗传学诊断（PGD）已取得了显著的成绩，其基本技术包括胚胎活检，PCR和FISH。本文就PGD的研究概况，活检标本来源，以PCR技术为基础的各类诊断技术的研究进展，影响PGE准确性的原因及未来的发展作一综述。     

跨断裂点探针及其在胚胎植入前遗传学诊断研究进展

植入前遗传学诊断(preimplantation genetic diagnosis，PGD)是产前诊断的一种新方案，理论上可避免以往产前诊断有异常而不得不终止妊娠的遗憾。染色体异常是PGD的很重要一部分，其中的染色体结构异常是PGD的难点之一。用目前商业化的探针不能区分正常和平衡易位的核型，针对各个病例的跨断裂点探针能区分这两种核型。本文就跨断裂点探针的技术路线、应用实例及其应用前景作一简要介绍。     

植入前遗传学诊断

植入前遗传学诊断是对卵细胞、受精卵、卵裂球或胚泡活检,主要是卵裂球活检,然后通过聚合酶链反应或荧光原位杂交行单细胞遗传学诊断。目前,移植前遗传学诊断面临着等位基因脱扣和染色体嵌合体等技术难题。我们相信,随着新技术新方法的不断发明创造,所有难题都会迎刃而解。     

The future of preimplantation genetic diagnosis

This paper reviews the current status of preimplantation genetic diagnosis (PGD), outlining the methods currently in use for the diagnosis of sex and single-gene defects. New approaches under development are described, e.g. fluorescent polymerase chain reaction (PCR), the use of sub-telomeric probes for patients with balanced reciprocal translocations, the analysis of first and second polar bodies, the use of lasers to facilitate the biopsy of embryos, and ways forward for infertile patients.     

New advances in human embryology: implications of the preimplantation diagnosis of genetic disease

The diagnosis of genetic disease in preimplantation embryosis discussed. The typing of spermatozoa may be feasible forfactors such as the presence of an X and Y chromosome. Embryosmight be typed by non-invasive methods, by assessing their uptakeof metabolites although the widest opportunities may arise bythe use of invasive methods which involve the removal of oneor a small number of cells. The methods of diagnosis are discussed,including enzyme assays and the use of DNA probes, preliminaryresults with human embryos are presented and the difficultiesrelated to these techniques are debated. The low rate of implantationof replaced embryos will mean that many embryos will have tobe diagnosed, and certain embryological factors such as thehigh incidence of chromosomal imbalance and the problems of‘imprinting’ might obscure certain diagnoses. Theadvantages and disadvantages of the method are discussed.     

Extending preimplantation genetic diagnosis: the ethical debate. Ethical issues in new uses of preimplantation genetic diagnosis

The use of preimplantation genetic diagnosis (PGD) to screen embryos for aneuploidy and genetic disease is growing. New uses of PGD have been reported in the past year for screening embryos for susceptibility to cancer, for late-onset diseases, for HLA-matching for existing children, and for gender. These extensions have raised questions about their ethical acceptability and the adequacy of regulatory structures to review new uses. This article describes current and likely future uses of PGD, and then analyses the ethical issues posed by new uses of PGD to screen embryos for susceptibility and late-onset conditions, for HLA-matching for tissue donation to an existing child, and for gender selection. It also addresses ethical issues that would arise in more speculative scenarios of selecting embryos for hearing ability or sexual orientation. The article concludes that except for sex selection of the first child, most current extensions of PGD are ethically acceptable, and provides a framework for evaluating future extensions for nonmedical purposes that are still speculative.     

Place of preimplantation diagnosis in genetic practice

Preimplantation genetic diagnosis (PGD) is currently one of the practical options available for couples at-risk to avoid the birth of children with genetic and chromosomal disorders. Despite its novelty, PGD has already become an alternative to traditional prenatal diagnosis, allowing establishing only unaffected pregnancies avoiding the risk for pregnancy termination. Indications for PGD have currently expanded beyond those practices in prenatal diagnosis, such as late-onset diseases with genetic predisposition, and preimplantation HLA typing with the purpose of establishing potential donor progeny for stem cell treatment of siblings, which makes PGD also an important compliment to prenatal diagnosis. The fact that more than 1,000 apparently healthy unaffected children have been born after PGD suggests its accuracy, reliability, and safety. PGD is presently an excellent option for carriers of balanced translocations, and appears to be of special value for avoiding age-related aneuploidies in patients of advanced reproductive age. The accumulated experience of thousands of PGD cycles for poor prognosis in vitro fertilization (IVF) patients provides strong evidence of the improvement of clinical outcome, particularly obvious from the reproductive history of patients. This makes of practical relevance to inform couples at-risk about availability of PGD option, so they make their own choice in avoiding the birth of affected offspring and having healthy children of their own.     

Preparing for preimplantation genetic diagnosis in France

Preimplantation genetic diagnosis (PGD) allows the detection of genetic defects before implantation, thus circumventing the possible need for abortion. France's current legislation allows the practice of PGD under certain circumstances which include the prerequisite agreement of the French health authority. Unfortunately, to enact the pending 'bioethical law', voted in July 1994, a decree still needs to be published. So, for the moment, although we know that PGD should be authorized, its practice is currently impossible in France. In order to prepare for licensing, we are setting up the relevant technologies, by performing biopsy on mouse embryos and fluorescent in-situ hybridization (FISH) experiments on human lymphoblast cells. We briefly describe the French legal situation with regard to PGD and the work we have performed in this context to obtain the licensing to offer PGD to patients. After a period of preparation, 95.9% of biopsies were successful and up to 95.4% of the biopsied blastomeres were properly spread onto slides. Biopsied and control mouse embryos were reimplanted into pseudopregnant females and similar birth rates were obtained (34.4 and 30.9% respectively). In these experiments we noticed a birth delay of 12-24 h for the biopsied embryos compared with the controls. Furthermore, scanning electron microscopy of the biopsied embryos allowed assessment of the hole made by the Tyrode's acid. By intercrossing adults derived from biopsied embryos for two successive generations, it was shown that the biopsy did not generate defects affecting their reproductive ability. FISH experiments were performed using specific probes for chromosomes X, Y and 1 on nuclei spread by a conventional protocol or a Tween/HCl blastomere spreading protocol; in the latter case, slides with 1-5 cells were prepared. A similar percentage of correct X,Y,1,1 signal was obtained from all three types of spreading, varying from 85.5 to 89.9%.      

Taskforce 5: preimplantation genetic diagnosis

The European Society of Human Reproduction and Embryology (ESHRE)Ethics Task Force sets out a recommended multidisciplinary approachto the application of preimplantation genetic diagnosis (PGD).The statement includes consideration of fundamental ethicalprinciples, specific problems in cases of high genetic risk,and PGD for aneuploidy screening, HLA typing and sex selectionfor non-medical reasons.     

Expert consensus on preimplantation genetic diagnosis and screening :Expert consensus on preimplantation genetic diagnosis and screening work groupCSCD

[No abstract available]     

植入前遗传学诊断的安全性和可靠性探讨

植入前遗传学诊断(preimplantation genetic diagnosis,PGD)是在胚胎植入前对配子或体外受精胚胎进行遗传学分析的一项诊断技术,目的在于从源头预防遗传性疾病的发生,从而改善有遗传性疾病高风险夫妇的妊娠结局.近年来,随着分子生物学技术的进步,越来越多遗传性疾病的发生机制被阐明,PGD的诊断范围逐渐扩展,其应用周期数也日益增多.新技术的开展如比较基因组杂交及其微阵列提高了PGD诊断的准确性.然而,这项技术的安全性问题也引起了人们高度重视.作者从透明带开孔技术、不同时期胚胎活检、胚胎活检细胞数目以及遗传分析技术的可靠性等方面对PGD的安全性进行了探讨.     

FISH应用于植入前遗传学诊断对高风险胚胎检测的研究

目的对固定好的单卵裂球进行FISH检测,在最短的时间内获得清晰可靠的信号,进行临床分析.方法选取发育不良的高风险胚胎分别进行分开变性和共变性后杂交的单细胞FISH,统计并分析其信号结果.结果共变性法信号获得率较分开变性法为高,并且信号获得率与变性方法相关(P=0.0486);共有9枚胚胎,42个卵裂球固定良好,其中二倍体信号36个,单倍体信号2个,21号染色体异常的胚胎为4︰9.结论初探分析人IVF废弃胚胎21号染色体异常几率较高.