Centre for Preimplantation Genetic Diagnosis, Guy's and St. Thomas' Hospital NHS Foundation Trust, London, UK.
Curr Opin Pediatr. 2010 Feb;22(1):28-34. doi: 10.1097/MOP.0b013e3283350d77.
This review will inform the clinician about the application, success rates and limitations of preimplantation genetic diagnosis (PGD) for haematologic disease to enable clinicians to offer couples with reproductive risk a realistic view of possible treatments. The molecular techniques used to diagnose disease mutations are described, including the newest technologies using whole genome amplification (WGA) and preimplantation genetic haplotyping (PGH) of embryos. The history and ethics involved in performing PGD together with human leukocyte antigen (HLA) testing (PGD-H) to create matched siblings suitable for haematopoietic stem cell transplant (HSCT) are discussed.
The greatest diagnostic hurdle in PGD is the paucity of molecular material in the single embryonic cell. WGA allows amplification of the entire genome, which greatly simplifies mutation analysis and increases the possibilities of multiple simultaneous genetic diagnoses. PGH can be applied to the amplified material, and may enable the application of PGD to the less common haematological mutations, and the diagnosis of nonaffected male progeny in cases of X-linked haematologic diseases.
PGD to exclude embryos carrying serious haematologic disease is a viable alternative to prenatal diagnosis for couples who wish to avoid having affected children and for whom therapeutic termination of affected pregnancies is unacceptable. PGD is not available for all haematologic mutations, is expensive, time consuming and does not guarantee a pregnancy. PGD-H is more diagnostically and ethically challenging, especially when there is the time constraint of urgent provision of HLA-matched stem cells for a sick sibling. To date there is only a handful of reported cases of successful HSCT from siblings created by embryo selection. The evolving technology of PGH following WGA may increase the diagnostic scope and availability of PGD in the future, but certain limitations will remain.
本篇综述旨在向临床医生介绍血液病植入前遗传学诊断（PGD）的应用、成功率和局限性，使临床医生能够为有生殖风险的夫妇提供可能治疗方法的现实观点。本文描述了用于诊断疾病突变的分子技术，包括使用全基因组扩增（WGA）和胚胎植入前遗传单体型分析（PGH）的最新技术。本文还讨论了进行 PGD 相关的历史和伦理问题，以及为造血干细胞移植（HSCT）创建匹配同胞供体而进行的人类白细胞抗原（HLA）检测（PGD-H）。
PGD 中最大的诊断障碍是单个胚胎细胞中缺乏分子物质。WGA 允许整个基因组的扩增，这极大地简化了突变分析，并增加了同时进行多种遗传诊断的可能性。PGH 可应用于扩增材料，并可能使 PGD 应用于较不常见的血液病突变，以及 X 连锁血液病中正常男性后代的诊断。
对于希望避免生育患病子女且不能接受终止患病妊娠的夫妇，排除携带严重血液病胚胎的 PGD 是产前诊断的可行替代方案。但 PGD 并非适用于所有血液病突变，费用昂贵、耗时且不能保证妊娠成功。PGD-H 在诊断和伦理方面更具挑战性，特别是在需要紧急提供 HLA 匹配的干细胞来治疗患病同胞的情况下。迄今为止，只有少数成功报道了通过胚胎选择创建的兄弟姐妹间进行 HSCT 的案例。WGA 后 PGH 的不断发展的技术可能会增加未来 PGD 的诊断范围和可用性，但某些局限性仍然存在。
