Juneau Caroline, Franasiak Jason, Treff Nathan
aReproductive Medicine Associates of New Jersey, Basking Ridge bRutgers, Robert Wood Johnson Medical School, New Brunswick, New Jersey, USA.
Curr Opin Obstet Gynecol. 2016 Jun;28(3):151-7. doi: 10.1097/GCO.0000000000000270.
Aneuploidy is a leading cause of pregnancy failure. Although initial attempts to perform preimplantation genetic screening did not improve outcomes, validated techniques were developed to safely and effectively increase pregnancy rates. Still, many embryos designated as euploid do not implant. Current approaches are being refined to provide additional biologic insight into why this is the case. At present, the diagnosis and clinical relevance of segmental aneuploidy and mosaicism are amongst the more heavily investigated.
Class I data have proven the safety of trophectoderm biopsy and validation studies have shown single nucleotide polymorphism array and quantitative PCR can accurately detect whole chromosome aneuploidy. Similar studies to validate next generation sequencing are underway. Although randomized control trials have demonstrated the clinical utility of preimplantation genetic screening, recent data on the impact of mosaicism and segmental aneuploidy require clarification.
Several well powered randomized control trials have shown preimplantation genetic screening improves implantation rate. Plausible explanations for euploid failures include undetected mosaicism and segmental aneuploidy. However, the true incidence and dispersion of mosaicism within the embryo is unknown. Likewise, the resolution of detection and clinical significance of segmental aneuploidy is unclear. Further research to validate proposed detection algorithms and class I data to determine if detection impacts outcomes is needed.
非整倍体是妊娠失败的主要原因。尽管最初进行植入前基因筛查的尝试并未改善妊娠结局，但已开发出经过验证的技术来安全有效地提高妊娠率。然而，许多被判定为整倍体的胚胎仍未着床。目前正在改进现有方法，以进一步深入了解其生物学原因。目前，节段性非整倍体和嵌合体的诊断及其临床相关性是研究较为深入的领域。
I类数据已证实滋养外胚层活检的安全性，验证研究表明单核苷酸多态性阵列和定量PCR能够准确检测全染色体非整倍体。验证下一代测序技术的类似研究正在进行中。尽管随机对照试验已证明植入前基因筛查具有临床实用性，但关于嵌合体和节段性非整倍体影响的最新数据仍需进一步阐明。
多项有力的随机对照试验表明，植入前基因筛查可提高着床率。整倍体胚胎着床失败的可能原因包括未检测到的嵌合体和节段性非整倍体。然而，胚胎中嵌合体的真实发生率和分布情况尚不清楚。同样，节段性非整倍体的检测分辨率及其临床意义也不明确。需要进一步开展研究以验证所提出的检测算法，并通过I类数据来确定检测是否会影响妊娠结局。
