[Genetic analysis of two families with abnormal findings upon prenatal diagnosis]

To carry out genetic analysis on two families with carriers of small terminal translocations using karyotyping analysis and genomic copy number variation sequencing (CNV-seq).

Two couples undergoing prenatal diagnosis at the Tianjin Central Hospital of Obstetrics and Gynecology respectively on April 12, 2020 and December 17, 2021 were selected as the study subjects. With informed consent, amniotic fluid and peripheral blood samples were collected and subjected to conventional karyotyping and CNV-seq analysis for the detection of chromosomal microdeletion/duplications.

Both couples had given births to children with chromosomal aberrations previously, and both fetuses were found to have abnormal karyotypes. CNV-seq showed that they had harbored microdeletion/duplications, and their mothers had both carried balanced translocations involving terminal fragments of chromosomes.

For fetuses with small chromosomal segmental abnormalities, their parental origin should be traced, and the diagnosis should be confirmed with combined genetic techniques.