Liao Yaping, Wang Liqun, Zhang Ding, Liu Changqing
Department of Cell Biology, Bengbu Medical College, Bengbu 233030, China.
Department of obstetrics and gynecology, the First Affiliated Hospital, Bengbu Medical College, Bengbu, Anhui, People's Republic of China.
Mol Cytogenet. 2014 Jun 5;7:39. doi: 10.1186/1755-8166-7-39. eCollection 2014.
Complex chromosome rearrangements (CCRs) are constitutional structural rearrangements involve more than two breakpoints on two or more chromosomes. Balanced CCR carriers are often phenotypically normal but associated with high risk of spontaneous abortion and having abnormal offspring with unbalanced karyotype. Here, we report a new familial case of complex chromosome structural aberrations involving chromosomes 3, 18 and 21 and four breakpoints.
Cytogenetic investigations showed a complex chromosomal chromosome rearrangement involving chromosomes 3, 18 and 21 with four breakpoints. 2 of 4 breakpoints were within the long arm of chromosome 18. Three-color fluorescence in situ hybridization (FISH) confirmed the complexity of the rearrangement and showed the derivative 21 to be composed of 3 distinct segments derived from chromosomes 21, 18, and 3. The karyotype of CCR carrier was determined as 46,XX,t(3;21;18)(3pter → 3q12::18q23 → 18qter;21pter → 21q22.1::18q21.1 → 18q23::3q12 → 3qter; 18pter → 18q21.1::21q22.1 → 21qter).
A new complex balanced CCR was characterized using conventional high resolution banding and molecular cytogenetic analysis. The results provided an explanation of recurrent abortion and abnormal child for balanced CCR carriers. Genetic counselling and prenatal diagnosis for couples with a balanced CCR is necessary since they have a high risk of having a child with unbalanced karyotype. Additional studies to reveal the molecular mechanism of CCRs would help reveal the rule of inherited CCRs in offspring.
复杂染色体重排（CCRs）是指涉及两条或更多条染色体上两个以上断点的结构性重排。平衡CCR携带者通常表型正常，但与自然流产风险高以及生育核型不平衡的异常后代有关。在此，我们报告了一例涉及3号、18号和21号染色体及四个断点的复杂染色体结构畸变的新家族病例。
细胞遗传学研究显示涉及3号、18号和21号染色体及四个断点的复杂染色体重排。4个断点中有2个位于18号染色体长臂内。三色荧光原位杂交（FISH）证实了重排的复杂性，并显示衍生的21号染色体由来自21号、18号和3号染色体的3个不同片段组成。CCR携带者的核型确定为46,XX,t(3;21;18)(3pter→3q12::18q23→18qter;21pter→21q22.1::18q21.1→18q23::3q12→3qter; 18pter→18q21.1::21q22.1→21qter)。
利用传统的高分辨率显带和分子细胞遗传学分析对一种新的复杂平衡CCR进行了特征描述。结果为平衡CCR携带者反复流产和子代异常提供了解释。由于平衡CCR携带者生育核型不平衡孩子的风险高，因此对其夫妇进行遗传咨询和产前诊断是必要的。进一步揭示CCRs分子机制的研究将有助于揭示CCRs在子代中的遗传规律。
