Garcia-Herrero S, Cervero A, Mateu E, Mir P, Póo M E, Rodrigo L, Vera M, Rubio C
Igenomix, Parc Científic Universitat de Valéncia, Valencia, Spain.
Igenomix, Parc Científic Universitat de Valéncia, Valencia, Spain.
Curr Top Dev Biol. 2016;120:421-47. doi: 10.1016/bs.ctdb.2016.04.009. Epub 2016 May 31.
Preimplantation development comprises the initial stages of mammalian development, before the embryo implants into the mother's uterus. In normal conditions, after fertilization the embryo grows until reaching blastocyst stage. The blastocyst grows as the cells divide and the cavity expands, until it arrives at the uterus, where it "hatches" from the zona pellucida to implant into the uterine wall. Nevertheless, embryo quality and viability can be affected by chromosomal abnormalities, most of which occur during gametogenesis and early embryo development; human embryos produced in vitro are especially vulnerable. Therefore, the selection of chromosomally normal embryos for transfer in assisted reproduction can improve outcomes in poor-prognosis patients. Additionally, in couples with an inherited disorder, early diagnosis could prevent pregnancy with an affected child and would, thereby, avoid the therapeutic interruption of pregnancy. These concerns have prompted advancements in the use of preimplantation genetic diagnosis (PGD). Genetic testing is applied in two different scenarios: in couples with an inherited genetic disorder or carriers of a structural chromosomal abnormality, it is termed PGD; in infertile couples with increased risk of generating embryos with de novo chromosome abnormalities, it is termed preimplantation genetic screening, or PGS.
植入前发育包括哺乳动物发育的初始阶段，即在胚胎植入母体子宫之前。在正常情况下，受精后胚胎生长直至达到囊胚阶段。随着细胞分裂和腔室扩大，囊胚不断生长，直到抵达子宫，在那里它从透明带“孵化”出来，植入子宫壁。然而，胚胎质量和活力可能会受到染色体异常的影响，其中大多数发生在配子发生和早期胚胎发育过程中；体外产生的人类胚胎尤其脆弱。因此，在辅助生殖中选择染色体正常的胚胎进行移植可以改善预后不良患者的治疗结果。此外，对于患有遗传性疾病的夫妇，早期诊断可以预防怀有患病胎儿的妊娠，从而避免治疗性终止妊娠。这些问题推动了植入前基因诊断（PGD）的应用发展。基因检测应用于两种不同情况：对于患有遗传性疾病的夫妇或结构性染色体异常的携带者，称为PGD；对于产生新发染色体异常胚胎风险增加的不育夫妇，称为植入前基因筛查，或PGS。
