A single center experience of prenatal parent-fetus trio exome sequencing for pregnancies with congenital anomalies.

OBJECTIVES

To examine the diagnostic yield of trio exome sequencing in fetuses with multiple structural defects with no pathogenic findings in cytogenetic and microarray analyses.

METHODS

We recruited 51 fetuses with two or more defects, non-immune fetal hydrops or fetal akinesia deformation syndrome|or fetal akinesia deformation sequence (FADS). Trio exome sequencing was performed on DNA from chorionic villi samples and parental blood. Detection of genomic variation and prioritization of clinically relevant variants was performed according to in-house standard operating procedures.

RESULTS

Median maternal and gestational age was 32.0 years and 21.0 weeks, respectively. Forty-three (84.3%) fetuses had two or more affected organ systems. The remaining fetuses had isolated fetal hydrops or FADS. In total, the exome analysis established the genetic cause for the clinical abnormalities in 22 (43.1%, 95% CI 29.4%-57.8%) pregnancies.

CONCLUSIONS

In fetuses with multiple defects, hydrops or FADS and normal standard genetic results, trio exome sequencing has the potential to identify genetic anomalies in more than 40% of cases.