Abstract：
OBJECTIVE: To carry out cyto- and molecular genetic analysis for a fetus with a ring chromosome identified through non-invasive prenatal testing (NIPT).
METHODS: A pregnant woman presented at the Shengjing Hospital Affiliated to China Medical University on May 11, 2021 was selected as the study subject. Maternal peripheral blood sample was screened by NIPT, and G-banded chromosomal karyotyping was carried out on amniotic fluid and peripheral blood samples from the couple. The fetus and the pregnant woman were also subjected to genomic copy number variation sequencing (CNV-seq), chromosomal microarray analysis (CMA), and fluorescence in situ hybridization (FISH) assay.
RESULTS: NIPT result suggested that the fetus had monomeric mosaicism or fragment deletion on chromosome 13. G banded chromosomal analysis showed that both the fetus and its mother had a karyotype of 47,XX,der(13)(pter→p11::q22→q10),+r(13)(::p10::q22→qter::), whilst her husband had a normal karyotype. FISH has verified the above results. No abnormality was detected with CNV-seq and CMA in both the fetus and the pregnant woman.
CONCLUSIONS: The ring chromosome 13 in the fetus has derived from its mother without any deletion, duplication and mosaicism. Both the fetus and the pregnant woman were phenotypically normal.
METHODS: A pregnant woman presented at the Shengjing Hospital Affiliated to China Medical University on May 11, 2021 was selected as the study subject. Maternal peripheral blood sample was screened by NIPT, and G-banded chromosomal karyotyping was carried out on amniotic fluid and peripheral blood samples from the couple. The fetus and the pregnant woman were also subjected to genomic copy number variation sequencing (CNV-seq), chromosomal microarray analysis (CMA), and fluorescence in situ hybridization (FISH) assay.
RESULTS: NIPT result suggested that the fetus had monomeric mosaicism or fragment deletion on chromosome 13. G banded chromosomal analysis showed that both the fetus and its mother had a karyotype of 47,XX,der(13)(pter→p11::q22→q10),+r(13)(::p10::q22→qter::), whilst her husband had a normal karyotype. FISH has verified the above results. No abnormality was detected with CNV-seq and CMA in both the fetus and the pregnant woman.
CONCLUSIONS: The ring chromosome 13 in the fetus has derived from its mother without any deletion, duplication and mosaicism. Both the fetus and the pregnant woman were phenotypically normal.
摘要：
目的：对通过非侵入性产前检测（NIPT）鉴定的具有环状染色体的胎儿进行细胞和分子遗传学分析。
方法：选取2021年5月11日在中国医科大学附属盛京医院就诊的一名孕妇作为研究对象。通过NIPT筛查母亲外周血样本，并对夫妇的羊水和外周血样本进行了G带染色体核型分析。胎儿和孕妇也进行了基因组拷贝数变异测序（CNV-seq），染色体微阵列分析（CMA），和荧光原位杂交(FISH)测定。
结果：NIPT结果表明胎儿在染色体13上有单体镶嵌或片段缺失。G显带染色体分析显示,胎儿及其母体的核型均为47,XX,der(13)(pter→p11::q22→q10)，+r(13)(::p10::q22→qter::)，而她丈夫的核型正常.FISH验证了上述成果。在胎儿和孕妇中均未检测到CNV-seq和CMA异常。
结论：胎儿的13号环状染色体来源于母体，没有任何缺失，重复和马赛克。胎儿和孕妇的表型均正常。
方法：选取2021年5月11日在中国医科大学附属盛京医院就诊的一名孕妇作为研究对象。通过NIPT筛查母亲外周血样本，并对夫妇的羊水和外周血样本进行了G带染色体核型分析。胎儿和孕妇也进行了基因组拷贝数变异测序（CNV-seq），染色体微阵列分析（CMA），和荧光原位杂交(FISH)测定。
结果：NIPT结果表明胎儿在染色体13上有单体镶嵌或片段缺失。G显带染色体分析显示,胎儿及其母体的核型均为47,XX,der(13)(pter→p11::q22→q10)，+r(13)(::p10::q22→qter::)，而她丈夫的核型正常.FISH验证了上述成果。在胎儿和孕妇中均未检测到CNV-seq和CMA异常。
结论：胎儿的13号环状染色体来源于母体，没有任何缺失，重复和马赛克。胎儿和孕妇的表型均正常。
