Dutta Usha R, Ponnala Rajitha, Dalal Ashwin
Diagnostics Division, Center for DNA Fingerprinting and Diagnostics, Tuljaguda complex, Andhra-Pradesh, India.
J Reprod Infertil. 2014 Apr;15(2):113-6.
Recurrent miscarriage is a major concern in the couples with reproductive problems. The chromosomal abnormalities, mainly balanced rearrangements are reported in variable phenotypes and the prevalence of them is 2-8% in such couples.
In this study, the clinical, cytogenetic and molecular cytogenetic evaluations were performed on a couple with RM. The cytogenetic analysis of the husband revealed a balanced reciprocal translocation of t(18;22)(q21.1;q12) whereas wife had a normal karyotype of 46,XX. Further spectral karyotyping was performed to rule out the involvement of any other chromosomal aberrations present in the genome. Additional whole chromosome paint FISH (Fluorescence in situ hybridization) with paint probes 18 and 22 confirmed the translocation.
To our knowledge, this is the first report of a novel (18;22) translocation with unique breakpoints and their association with RM. The reciprocal translocations provide a good opportunity for the identification of disease associated genes. However, in recurrent miscarriages, most of them do not disrupt any gene at the breakpoint but can lead to unbalanced gametes and hence poor reproductive outcome like RM or birth of a child with malformations and intellectual disability. The translocation breakpoints might be risk factors for RM. Moreover, the impact of the balanced translocations in association with RM is discussed in this report.
复发性流产是有生殖问题的夫妇主要关注的问题。据报道,染色体异常主要是平衡重排在不同表型中存在,在这类夫妇中的发生率为2%至8%。
在本研究中,对一对复发性流产夫妇进行了临床、细胞遗传学和分子细胞遗传学评估。丈夫的细胞遗传学分析显示存在t(18;22)(q21.1;q12)平衡易位,而妻子核型正常,为46,XX。进一步进行光谱核型分析以排除基因组中存在的任何其他染色体畸变。使用18号和22号染色体涂染探针进行的额外全染色体涂染荧光原位杂交(FISH)证实了该易位。
据我们所知,这是首次报道具有独特断点的新型(18;22)易位及其与复发性流产的关联。相互易位为鉴定疾病相关基因提供了良好机会。然而,在复发性流产中,大多数相互易位在断点处并未破坏任何基因,但可导致配子不平衡,从而导致不良生殖结局,如复发性流产或出生有畸形和智力残疾的孩子。易位断点可能是复发性流产的危险因素。此外,本报告还讨论了平衡易位与复发性流产的关联影响。