Evaluating the Effectiveness of Quantitative Fluorescent Polymerase Chain Reaction as a Substitute or Complement to Conventional Karyotyping for Prenatal Diagnosis.

BACKGROUND

This study endeavors to assess the efficacy of quantitative fluorescent polymerase chain reaction (QF-PCR) as an alternative adjunctive modality to conventional karyotyping for prenatal diagnostic purposes.

METHODS

In this cohort study, 464 pregnant women deemed at high risk for chromosomal aneuploidies within gestational age 12-24 weeks, spanning from January 2020 to May 2023 were enrolled. Analysis was done on 347 women who underwent both QF-PCR and karyotype.

RESULTS

Within this cohort, concordant QF-PCR and karyotype results were achieved in 332 (95.67%) samples with 21 women showing trisomy 21 and two trisomy 18 in the fetus with results being 100% concordant with karyotype and QF-PCR. Notably, there were no false-negative or false-positive QF-PCR results. However, eleven cases presented discordant results, revealing various genetic abnormalities, such as deletions, translocations, inversions, and mosaicism. The overall frequency of chromosomal abnormalities was 8.82% (41/464). The mean age of the pregnant women was 28.7 ± 5.54 years, with 10.7% (50/464) of women having aged > 35 years. The median gestation age for amniocentesis and CVS procedures was 16 weeks (IQR 15.6-20) and 13 weeks (IQR 12.7-13.5), respectively.

CONCLUSION

The study concluded that although QF-PCR may serve as a stand-alone diagnostic tool in some cases with appropriate pretest counseling, simultaneous karyotyping, or chromosomal microarray should be considered in pregnancies with normal QF-PCR results and abnormal USG findings such as increased nuchal translucency or structural malformations or a family history of a chromosomal disorder. Despite being a rapid and highly sensitive test, QF-PCR does not fully substitute conventional karyotype analysis.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13224-024-02032-1.