Wilton Leeanda
Genetic and Molecular Research, Melbourne IVF, 320 Victoria Parade, East Melbourne 3002, Victoria, Australia.
Hum Reprod Update. 2005 Jan-Feb;11(1):33-41. doi: 10.1093/humupd/dmh050. Epub 2004 Nov 29.
Numerical chromosome errors are known to be common in early human embryos and probably make a significant contribution to early pregnancy loss and implantation failure in IVF patients. Over recent years fluorescent in situ hybridization (FISH) has been used to document embryonic aneuploidies. Many IVF laboratories perform preimplantation genetic diagnosis (PGD) with FISH to select embryos that are free from some aneuploidies in an attempt to improve implantation, pregnancy and live birth rates in particular categories of IVF patients. The usefulness of FISH is limited because only a few chromosomes can be detected simultaneously in a single biopsied cell. Complete karyotyping at the single cell level can now be achieved by comparative genomic hybridization (CGH). CGH enables not only enumeration of all chromosomes but gives a more complete picture of the entire length of each chromosome and has demonstrated that chromosomal breakages and partial aneuploidies exist in embryos. CGH has provided invaluable information about the extent of mosaicism and aneuploidy of all chromosomes in early human conceptuses. CGH has been applied to clinical PGD and has resulted in the birth of healthy babies from embryos whose full karyotype was determined in the preimplantation phase.
已知染色体数目错误在早期人类胚胎中很常见，可能是导致体外受精（IVF）患者早期妊娠丢失和着床失败的一个重要因素。近年来，荧光原位杂交（FISH）已被用于记录胚胎非整倍体情况。许多IVF实验室采用FISH进行植入前基因诊断（PGD），以挑选出无某些非整倍体的胚胎，试图提高特定类型IVF患者的着床率、妊娠率和活产率。FISH的作用有限，因为在单个活检细胞中只能同时检测少数几条染色体。现在通过比较基因组杂交（CGH）能够在单细胞水平上实现完整的核型分析。CGH不仅能对所有染色体进行计数，还能更全面地呈现每条染色体的全长情况，并且已证实胚胎中存在染色体断裂和部分非整倍体现象。CGH为早期人类胚胎中所有染色体的嵌合现象和非整倍体程度提供了宝贵信息。CGH已应用于临床PGD，并已使在植入前阶段确定了完整核型的胚胎孕育出健康婴儿。
