Clinical Significance of Conventional Karyotype and QF-PCR in Detection of Fetal Chromosomal Abnormalities

Abstract

This study aims to compare the advantages of two widely used methods for fetal chromosomal detection, karyotyping and QF-PCR, together with the indications for invasive prenatal diagnosis. We retrospectively investigated 888 amniocenteses analyzed by karyotyping only or karyotyping combined with QF-PCR. We assessed the results of each method and compared them to the indications for prenatal testing including maternal age, fetal ultrasound findings, and serum screening. We found 39 (4.4%) abnormalities, where 59% of those abnormalities were numerical and 41% were structural abnormalities undetectable by QF-PCR methods. Many structural abnormalities do not have clinical significance and we found that 23% of found structural abnormalities were clinically significant but undetectable by QF-PCR (0.3% of all amniocentesis analyzed). Additional 23% of found structural abnormalities were balanced translocations which can have rare clinically significant consequences. In total, 46% of found structural abnormalities had possible clinical consequences, which were undetectable by QF-PCR, or by noninvasive prenatal testing for five common aneuploidies. Thus, QF-PCR is a reliable method to detect most common fetal aneuploidies, but karyotyping should be used if any other chromosomal abnormalities are suspected. Even though QF-PCR is a fast and reliable method, physicians should be aware of the limitations of various methodologies for detection of fetal abnormalities and assign the proper method to the indication for amniocentesis.

Keywords

Karyotype - QF-PCR - Fetal abnormalities - Trisomy 21

Publication History

Received: 06 May 2016

Accepted: 02 November 2016

Article published online:
08 May 2023