Liehr Thomas, Weise Anja, Mrasek Kristin, Ziegler Monika, Padutsch Niklas, Wilhelm Kathleen, Al-Rikabi Ahmed
Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Jena, Germany.
Front Genet. 2019 Nov 14;10:1165. doi: 10.3389/fgene.2019.01165. eCollection 2019.
A balanced pericentric inversion is normally without any clinical consequences for its carrier. However, there is a well-known risk of such inversions to lead to unbalanced offspring. Inversion-loop formation is the mechanism which may lead to duplication or deletion of the entire or parts of the inverted segment in the offspring. However, also partial deletion and duplication may be an effect of a parental inversion, depending on the size of the inversion and the uneven number of crossing over events, also suggested to be due to an inversion loop. Here we describe two new cases of recombinant chromosomes and provide a review of the literature of comparable cases. Interestingly, this survey confirmed the general genetic principle that gain of copy numbers are better tolerated than losses. Furthermore, there is a non-random distribution of all human chromosomes concerning their involvement in recombinant formation, which is also discussed.
平衡的臂间倒位通常对携带者没有任何临床影响。然而，众所周知，这种倒位有导致后代染色体不平衡的风险。倒位环形成是可能导致后代中整个或部分倒位片段重复或缺失的机制。然而，部分缺失和重复也可能是亲代倒位的结果，这取决于倒位的大小以及交叉事件数量不均，这也被认为是由于倒位环所致。在此，我们描述了两例重组染色体的新病例，并对类似病例的文献进行了综述。有趣的是，这项调查证实了一般的遗传学原理，即拷贝数增加比减少更易被耐受。此外，还讨论了所有人类染色体在参与重组形成方面的非随机分布情况。
