Multiplex ligation-dependent probe amplification (MLPA): a reliable alternative for fetal chromosome analysis?

Abstract

Objective: To determine whether molecular karyotyping using multiple ligation probe amplification (MLPA) is a reliable alternative for quick and accurate diagnosis of fetal chromosomal abnormalities. Methods: MLPA, using specialised probe sets designed to detect aneuploidy, major chromosomal rearrangements and recognised microdeletion syndromes, was used to analyse chorionic villi or amniocytes left after traditional karyotypingof 476 fetuses for clinical indications. Results: An abnormal result was obtained in 190 cases, including 124 trisomies, 21 sex chromosome anomalies, 14 triploidies, and 31 rearrangements or mosaics. All trisomies were detected by all three techniques, but triploidies were only detected by karyotyping and QF-PCR. In 19 of the 31 cases of rearrangements or mosaicism there was an uncertain or high risk of adverse outcome. Traditional karyotyping detected 13 of the 19 pathogenic rearrangements, MLPA detected 18, and QF-PCR did not detect any. Conclusion: MLPA, using specialized probe sets, detects more chromosomal rearrangements, conferring significant risk of adverse outcome than karyotyping. A combination of qfPCR and MLPA could be a good, rapid alternative to current practice. In the future, used in conjunction with non-invasive prenatal diagnosis based on cell free fetal DNA it might provide a rapid and efficient approach to fetal karyotyping.

Keywords::

• Fetal chromosomal analysis
• microdeletion syndromes
• prenatal diagnosis

Declaration of Interest: Lisa Levett and Stuart Liddle are currently employed by The Doctors Laboratory or its subsidiaries offering prenatal diagnostic testing and therefore a potential conflict of interest exists. James Kistler was employed by The Doctors Laboratory. This work was funded by the charity Newlife. LSC receives some funding from the UCLH NHS Biomedical Research Centre and the Great Ormond Street Children’s Charity.