Munné S, Bahçe M, Schimmel T, Sadowy S, Cohen J
Institute for Reproductive Medicine and Science, Saint Barnabas Medical Center, Livingston, NJ 07039, USA.
Prenat Diagn. 1998 Dec;18(13):1450-8.
Preimplantation genetic diagnosis of translocations can be performed on first polar bodies (PB) at metaphase stage using FISH with whole-chromosome painting DNA probes. Here we report the use of this method in a couple in which the female was a carrier of a balanced translocation 46,XX,t(11;16)(q21;q22). This case unusual in that two polar bodies showed recombination events between the homologue chromosomes of 11 and 16 pairs, resulting in M-II oocytes with monovalent chromosomes having a normal and a derivative chromatid. For this type of case, PGD analysis on polar bodies cannot give a useful result, because, at the second meiotic division, either of these chromatids could remain in the oocyte, resulting in a normal, balanced or unbalanced embryo. PGD analysis on blastomeres can provide a solution. 11 previous cases of PGD of translocations performed by metaphase PB analysis are reviewed.
易位的植入前基因诊断可在中期阶段的第一极体（PB）上进行，使用全染色体涂染DNA探针的荧光原位杂交技术（FISH）。在此，我们报告该方法在一对夫妇中的应用，其中女方是平衡易位46,XX,t(11;16)(q21;q22)的携带者。该病例不同寻常之处在于，两个极体显示出11号和16号同源染色体之间的重组事件，导致处于减数第二次分裂中期（M-II）的卵母细胞带有单价染色体，每条单价染色体具有一条正常染色单体和一条衍生染色单体。对于这类病例，对极体进行植入前基因诊断分析无法得出有用结果，因为在第二次减数分裂时，这两条染色单体中的任何一条都可能留在卵母细胞中，从而产生正常、平衡或不平衡的胚胎。对卵裂球进行植入前基因诊断分析可以提供一个解决方案。本文回顾了之前11例通过中期极体分析进行易位植入前基因诊断的病例。
