Differences in Prenatal and Postnatal Phenotypic Evaluations in Patients With Congenital Anomalies and Known Genetic Diagnoses.

OBJECTIVES

Gaps exist in the understanding of the presentation of genetic conditions across the lifespan, especially the prenatal period. This study describes the limitations of prenatal phenotyping among neonates with genetic conditions.

METHODS

We collected prenatal and postnatal phenotypes via retrospective chart review of neonates with genetic diagnoses who previously received fetal ultrasound, MRI, and echocardiogram at the Cincinnati Children's Fetal Care Center (CCFCC) between July 2018 and October 2022.

RESULTS

For 83 neonates with genetic diagnoses, the number of phenotypic findings significantly increased after postnatal evaluation (mean: 10.01) compared with what was identified during prenatal evaluation (mean: 4.65; p < 0.001). There was a significant increase in the number of anomalies noted postnatally in most body systems, including the musculoskeletal, nervous, and respiratory systems.

CONCLUSIONS

There are significant increases in phenotypic findings prenatally and after birth. Fetuses with anomalies should be evaluated multiple times, particularly when a genetic etiology is suspected, to aid in phenotype-driven genetic testing. Identifying diagnoses during the prenatal period allows time for families to adapt perinatal medical management decisions or post-birth plans, such as adoption. Awareness of phenotypes that are difficult to evaluate may improve variant curation by placing less value in the absence of findings that may be characteristic of a disorder.