Identification of a fetus with complex chromosomal structural aberration by next-generation sequencing and karyotype analysis

Abstract

To perform prenatal diagnosis for a woman carrying a balanced translocation. Clinical phenotype of the woman and her first child was analyzed. Peripheral blood sample of the woman and amniotic fluid sample from two subsequent pregnancies were subjected to chromosomal karyotyping and copy number variation analysis through next-generation sequencing (NGS). The karyotypes of the woman and her first child were determined as 46,XX,t(5;6)(p15:p23) and 46,XX,?der(5),t(5;6)(p15.32;p22.3), respectively. The karyotype of the amniocyte from her second pregnancy was 46,XN,t(5;6)(p15:p23). No pathogenic copy number variation was detected. The karyotype of her third pregnancy was 46,XN,?der(5),t(5;6)(p15.32;p22. 3), in addition with a 6.04 Mb deletion at 5p15.33p15.32 (20 000 - 6 060 000) and a 18.50 Mb duplication at 6p25.3p22.3 (160 000 - 18 660 000). Combined karyotyping analysis and NGS has enabled detection of fetal copy number variations for a woman carrying a balanced chromosomal translocation.