[Application of BACs-on-Beads in prenatal diagnosis].

Objective: To explore the value of BACs-on-Beads (BoBs) for the practice of prenatal diagnosis.

Methods: The results of chromosomal karyotyping and BoBs of 1773 prenatal samples were compared. Microdeletions and microduplications detected by BoBs were subjected to chromosome microarray analysis (CMA) with informed consent from patients.

Results: BoBs has detected 46 cases of common aneuploidies involving chromosomes 13, 18, and 21, and 16 cases involving X and Y chromosomes. For 4 fetuses with normal results by BoBs, karyotyping analysis of amniotic fluid sample suggested low percentage mosaicisms (< 20%). BoBs has detected none of the 9 common microdeletions, but 14 male fetuses with Xp22 microdeletions and 5 with other microdeletions/microduplications. In 10 cases, the couples had chosen CMA verification, and the results were all consistent.

Conclusion: As a rapid diagnostic technique, BoBs has a high accuracy for common aneuploidies, and is capable of discovering certain chromosome microdeletions and microduplications. The difficulty lies in the inability to detect low proportion mosaicisms and the consultation following detection for male fetuses carrying Xp22 microdeletions.