Postnatal genetic testing on cord blood for prenatally identified high-probability cases

Area of Science:

• Medical Genetics
• Neonatal Care
• Prenatal Diagnostics

Background:

• Prenatal screening identifies fetuses at high risk for genetic abnormalities.
• Timely genetic diagnoses are crucial for effective neonatal management.
• Umbilical cord blood (CB) offers a readily available postnatal sample for genetic analysis.

Purpose of the Study:

• To assess the clinical utility of postnatal genetic testing on umbilical cord blood (CB).
• To evaluate the effectiveness of CB genetic testing for prenatally identified high-probability fetuses.
• To determine the impact of CB genetic testing on neonatal management and diagnostic timelines.

Main Methods:

• CB samples were collected from 2016-2021 for individuals meeting specific criteria (fetal anomaly, positive cfDNA/biochemical screening, family history).
• Genetic testing included karyotype, chromosomal microarray (CMA), and other molecular analyses.
• Data on diagnostic yield, turnaround time, and impact on neonatal management were analyzed.

Main Results:

• Genetic testing yielded a diagnosis in 23.4% of neonates (92/393).
• The majority of diagnoses (73.9%) potentially impacted neonatal management.
• Testing turnaround time averaged 10.3 days, facilitating prompt clinical decisions.

Conclusions:

• Postnatal genetic testing on CB is valuable for prenatally identified high-probability fetuses.
• This testing enables timely genetic diagnoses and informs neonatal care strategies.
• CB genetic testing reduces the postnatal diagnostic odyssey and provides reassurance to families.