Zhu Jian Jiang, Qi Hong, Cai Li Rong, Wen Xiao Hui, Zeng Wen, Tang Guo Dong, Luo Yao, Meng Ran, Mao Xue Qun, Zhang Shao Qin
Prenatal Diagnosis Center, Beijing Haidian Maternal and Child Health Hospital, Beijing, 100080 People's Republic of China.
Mol Cytogenet. 2019 Sep 18;12:41. doi: 10.1186/s13039-019-0453-1. eCollection 2019.
In prenatal diagnosis, CMA has begun to emerge as a favorable alternative to karyotype analysis, but it could not identify balanced translocations, triploidies, inversion and heteromorphisms. Therefore, conventional cytogenetic and specific staining methods still play an important role in the work-up of chromosome anomaly. This study investigated the application of C-banding and AgNOR-staining techniques in prenatal diagnosis of chromosomal heteromorphisms and some structure abnormalities.
Among the 2970 samples, the incidence of chromosomal heteromorphisms was 8.79% (261/2970). The most frequent was found to be chromosome Y (2.93%, 87/2970), followed by chromosome 1 (1.65 %, 49/2970), 9 (1.52 %, 45/2970), 22 (0.77 %, 23/2970) and 15 (0.64 %, 19/2970). We compared the incidence of chromosomal heteromorphisms between recurrent spontaneous abortion (RSA) group and control group. The frequency of autosomal hetermorphisms in RSA group was 7.63% higher than that in control group (5.78%), while the frequency of Y chromosomal heteromorphisms was 4.76% lower than that in control group (5.71%). Here we summarized 4 representative cases, inv (1) (p12q24), psu dic (4;17) (p16.3;p13.3), r(X)(p11; q21) and an isodicentric bisatellited chromosome to illustrate the application of C-banding or AgNOR-staining, CMA or NGS was performed to detect CNVs if necessary.
This study indicated that C-banding and AgNOR-staining were still effective complementary methods to identify chromosomal heteromorphisms and marker chromosomes or some structural rearrangements involving the centromere or acrocentric chromosomes. Our results suggested that there was no evidence for an association between chromosomal heteromorphisms and infertility or recurrent spontaneous abortions. Undoubtedly, sometimes we needed to combine the results of CMA or CNV-seq to comprehensively reflect the structure and aberration of chromosome segments. Thus, accurate karyotype reports and genetic counseling could be provided.
在产前诊断中，染色体微阵列分析（CMA）已开始成为核型分析的一种有利替代方法，但它无法识别平衡易位、三倍体、倒位和异态性。因此，传统的细胞遗传学和特异性染色方法在染色体异常的检查中仍发挥着重要作用。本研究探讨了C带和银染核仁组织区（AgNOR）染色技术在染色体异态性和一些结构异常产前诊断中的应用。
在2970份样本中，染色体异态性的发生率为8.79%（261/2970）。最常见的是Y染色体（2.93%，87/2970），其次是1号染色体（1.65%，49/2970）、9号染色体（1.52%，45/2970）、22号染色体（0.77%，23/2970）和15号染色体（0.64%，19/2970）。我们比较了反复自然流产（RSA）组和对照组之间染色体异态性的发生率。RSA组常染色体异态性的频率比对照组（5.78%）高7.63%，而Y染色体异态性的频率比对照组（5.71%）低4.76%。这里我们总结了4个代表性病例，inv(1)(p12q24)、psu dic(4;17)(p16.3;p13.3)、r(X)(p11;q21)和一条等臂双随体染色体，以说明C带或AgNOR染色的应用，必要时进行CMA或二代测序（NGS）以检测拷贝数变异（CNV）。
本研究表明，C带和AgNOR染色仍然是识别染色体异态性和标记染色体或一些涉及着丝粒或近端着丝粒染色体的结构重排的有效补充方法。我们的结果表明，没有证据表明染色体异态性与不孕或反复自然流产之间存在关联。毫无疑问，有时我们需要结合CMA或CNV测序的结果，以全面反映染色体片段的结构和畸变情况。从而能够提供准确的核型报告和遗传咨询。
