Background 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. Results 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. Conclusions 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.

中文翻译：

---

C显带和AgNOR染色仍然是产前诊断中鉴定染色体异态性和某些结构异常的有效补充方法。

背景 在产前诊断中，CMA 已开始成为核型分析的有利替代方案，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然发挥着重要作用。本研究探讨了 C 显带和 AgNOR 染色技术在染色体异态性和某些结构异常产前诊断中的应用。结果2970份样本中，染色体异态性发生率为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（0.64%，19/2970）。我们比较了复发性自然流产（RSA）组和对照组之间染色体异态性的发生率。RSA组常染色体异态性频率较对照组（5.78%）高7.63%，Y染色体异态性频率较对照组（5.71%）低4.76%。这里我们总结了4个代表性案例，inv (1) (p12q24)、psu dic (4;17) (p16.3;p13.3)、r(X)(p11; q21)和等双着丝粒双卫星染色体来说明其应用必要时进行 C 带或 AgNOR 染色、CMA 或 NGS 检测 CNV。结论 本研究表明，C 显带和 AgNOR 染色仍然是鉴定染色体异态性和标记染色体或涉及着丝粒或近端着丝粒染色体的某些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症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-seq的结果来综合反映染色体片段的结构和畸变。因此，可以提供准确的核型报告和遗传咨询。