Identification of Complex Chromosomal Rearrangement Involving Chromosomes 10, 18, and 19 in a Family Undergoing Prenatal Diagnosis: Case Report.

Complex chromosomal rearrangements (CCRs) are rare chromosomal structural abnormalities that are often difficult to be detected. Chromosome conformation-based karyotyping (c-Moka) is an emerging technology designed to analyze the three-dimensional structure of chromosomes, thereby identifying various types of chromosomal structural variations. In our study, conventional karyotyping was performed for a gravida with a high risk of sex chromosome abnormality, as indicated by non-invasive prenatal testing. The analysis suggested a potential chromosome translocation at the terminals of chromosomes 18 and 19. Subsequently, fluorescence in situ hybridization (FISH) was performed at metaphase stage using a 19p13.3 probe. The signal was detected on other chromosome rather than chromosome 18, leading us to hypothesize that the subject might have CCRs that was not identifiable through conventional karyotyping and FISH. To further investigate, we employed c-Moka, which revealed CCRs involving chromosomes 10, 18 and 19. Ultimately, the karyotype of the subject was determined to be 46,XX,t(10;18;19)(q26.3;p11.21;p13.3). This study underscores that, compared to conventional karyotyping, c-Moka has significant advantages in detecting CCRs.