CNV-seq联合细胞检测技术对额外小标记染色体的产前诊断和遗传学分析

Prenatal diagnosis and genetic analysis of small supernumerary marker chromosome using CNV-seq combined with cytogenetic techniques

摘要

目的 探讨采用分子和多种细胞遗传学检测技术对携带额外小标记染色体(sSMC)的胎儿进行产前诊断的价值及临床意义。方法 回顾性分析2018年1月至2024年12月在柳州市妇幼保健院和广州市妇女儿童医疗中心柳州医院行产前诊断的32 876例孕妇,对胎儿产前诊断样本(绒毛、羊水和脐血)进行细胞培养和染色体 G 显带核型分析,对携带有sSMC的样本进一步行低深度全基因组拷贝数变异测序技术(CNV-seq)检测其来源及致病性,必要时结合 C 和 N 显带技术分析sSMC 的组成。结果 在32 876例产前诊断样本中共检出35例携带sSMC核型的胎儿,总检出率为1.1‰,其中纯合型的sSMC 有21例,占总数的60%(21/35);嵌合型的sSMC有14例,占总数的40%(14/35)。对携带sSMC的35例胎儿进一步行CNV-seq检测,发现16例含致病性拷贝数变异,分别涉及到1、4、9、10、11、12、15、18、22、X、Y 等染色体,其中只有1例妊娠到足月分娩,剩余15例均终止妊娠;19例非致病性的sSMC中,2例引产,1例死胎,16例妊娠至足月分娩,后期电话随访未见异常。结论 将细胞和分子遗传学检测技术结合起来对sSMC的大小、来源进行分析,可明确其致病性,为携带sSMC胎儿的产前诊断和遗传咨询提供理论依据。

Abstract

Objective To explore the value and clinical significance of applying molecular and cytogenetic techniques in the prenatal diagnosis of fetuses carrying a small supernumerary marker chromosome (sSMC). Methods A retrospective analysis was conducted on 32 876 pregnant women who underwent prenatal diagnosis at Liuzhou Maternity and Child Healthcare Hospital and Guangzhou Women and Children's Medical Center Liuzhou Hospital from January 2018 to December 2024.Prenatal samples,including chorionic villi,amniotic fluid,and umbilical cord blood,were subjected to cell culture and G-banded karyotype analysis.Samples identified with sSMC were further analyzed using copy number variation sequencing (CNV-seq) to determine their chromosomal origin and pathogenicity.When necessary,C-banding and N-banding techniques were used to further characterize the composition of the sSMC. Results Among the 32 876 prenatal diagnostic samples,35 fetuses with sSMC karyotypes were identified,with an overall detection rate of 1.1‰.Of these,21 cases (60%,21/35) were non-mosaic sSMC,and 14 cases (40%,14/35) were mosaic sSMC. CNV-seq analysis of the 35 fetuses revealed pathogenic copy number variations in 16 cases, involving chromosomes 1,4,9,10,11,12,15,18,22,X,and Y.Among these cases,only one pregnancy resulted in a full-term live birth,while the remaining 15 pregnancies were terminated.Among the 19 cases with non-pathogenic sSMC,two pregnancies were terminated,one resulted in stillbirth,and 16 continued to full-term delivery.Follow-up by telephone revealed no abnormalities in these infants. Conclusion The combination of cytogenetic and molecular genetic techniques enables accurate determination of the size and origin of sSMCs and facilitates the assessment of their pathogenicity.This approach provides an important theoretical basis for the prenatal diagnosis and genetic counseling of fetuses carrying sSMCs.

关键词

胎儿 / 额外小标记染色体 / 低深度全基因组拷贝数变异测序技术 / 产前诊断

Key words

fetus / small supernumerary marker chromosome / copy number variation sequencing / prenatal diagnosis

参考文献

[1] 潘虹. 额外小标记染色体的特点、产前诊断和遗传咨询[J]. 中华围产医学杂志, 2012, 15(10): 588-591.

[2] Huang M H, Lee C, Chang J S, et al. Retrospectively investigating the 12-year experience of prenatal diagnosis of small supernumerary marker chromosomes through array comparative genomic hybridization[J]. Taiwan J Obstet Gynecol, 2019, 58(1): 139-144.

[3] Karamysheva T, Gayner T A, Zakirdva E G, et al. New sight on assessment of clinical value of human supernumerary marker chromosomes[J]. Russ J Genet, 2020. 56: 530-539.

[4] Liehr T, Claussen U, Starke H. Small supernumerary marker chromosomes (sSMC) in humans[J]. Cytogenet Genome Res, 2004, 107(1-2): 55-67.

[5] Liehr T, Weise A. Frequency of small supernumerary marker chromosomes in prenatal,newborn,developmentally retarded and infertility diagnostics[J]. Int J Mol Med, 2007, 19(5): 719-731.

[6] Liehr T. Small supernumerary marker chromosomes-an update[J]. Mol Cytogenet, 2014, 7(Suppl 1): I11.

[7] 郭利丽, 丁建林, 王少帅. 产前诊断中 CNV-seq与核型分析联合应用的意义[J]. 中国产前诊断杂志(电子版), 2020, 12(4): 27-31.

[8] Wu X, Xie X, Su L, et al. Prenatal diagnosis of Pallister-Killian syndrome and literature review[J]. J Cell Mol Med, 2021, 25(18): 8929-8935.

[9] Kilijanova D, Hynek M, Prosová B, et al. EP13.02:Prenatal diagnosis of Emanuel syndrome:a case report[J]. Ultrasound Obstet Gynecol, 2017, 50: 312.

[10] Liehr T, Mrasek K, Hinreiner S, et a1. Small supernumerary marker chromosomes (sSMC) in patients with a 45,X/46,X,+mar karyotype-17 new cases and a review of the literature[J]. Sex Dev, 2007, 1(6): 353-362.

[11] 郑慧玲, 杨雪, 郑琳, 等. 产前诊断中额外标记染色体的遗传学分析[J]. 中国妇幼健康研究, 2025, 36(2): 89-94.

[12] 席惠, 王华, 贾政军, 等. 联合运用多种技术鉴别四例胎儿新发标记染色体[J]. 中国优生与遗传杂志, 2013, 21(10): 25-27,39.

[13] 徐玉婵, 韦德宁, 罗颖花, 等. C 显带和 N 显带技术在标记染色体和双着丝粒染色体辅助诊断中的应用[J]. 检验医学与临床, 2021, 18(6): 793-796.

[14] 钟丽娟, 陈艳, 钟容, 等. CNV-seq结合染色体核型分析技术在产前诊断胎儿染色体异常中的价值观察[J]. 中国妇幼健康研究, 2024, 35(8): 69-75.

基金资助

广西壮族自治区卫生健康委员会科研课题(Z-B20231522)

广西壮族自治区卫生健康委员会科研课题(Z20210767)

广西壮族自治区卫生健康委员会科研课题(Z-B20251182)

广西壮族自治区卫生健康委员会科研课题(Z-B20251178)