QF‐PCR as a stand‐alone test for prenatal samples: the first 2 years' experience in the London region

Abstract

Objective To analyse the results of the first 2 years of a QF-PCR stand-alone testing strategy for the prenatal diagnosis of aneuploidy in the London region and to determine the advantages and disadvantages of this policy.Methods A review of the results of 9737 prenatal samples received for exclusion of chromosome abnormalities. All samples were subjected to QF-PCR testing for common aneuploidies but only samples fulfilling specific criteria subsequently had a full karyotype analysis. ResultsOf the 9737 samples received, 10.3% had a chromosome abnormality detected by QF-PCR testing. Of the 7284 samples received with no indication for karyotype analysis, 25 (0.3%) received a normal QF-PCR result but subsequently had an abnormal karyotype detected either prenatally as a privately funded test or postnatally. Of these samples, without subsequent abnormal ultrasound findings, five had a chromosome abnormality associated with a poor prognosis, representing 0.069% of samples referred for Down syndrome testing.Conclusion While back-up karyotyping is required for some samples, using QF-PCR as a stand-alone prenatal test for pregnancies without ultrasound abnormalities reduces costs, provides rapid delivery of results, and avoids ambiguous and uncertain karyotype results, reducing parental anxiety.

Is prenatal cytogenetic diagnosis with genomic array indicated in pregnancies at risk for a molecular or metabolic disorder?

“…A few years ago, several laboratories introduced rapid aneuploidy testing for detection of trisomy 13, 18, and 21, triploidy, and aneuploidy of sex chromosomes as a standalone test for molecular and metabolic referrals. 1,2 Recent advances in microarray testing in pregnancies without ultrasound anomalies led to new insights into the prevalence of submicroscopic chromosome aberrations in such fetuses. Some large-scale studies showed a significant percentage (0.5%) of pathogenic submicroscopic findings in pregnancies tested due to advanced maternal age or abnormal first-trimester screening.…”

FISH is not Suitable as a Standalone Test for Detecting Fetal Chromosomal Abnormalities

“…In discolored or blood-stained samples subjected to FISH, maternal-cell contamination cannot be ruled out, if the fetus is not a male. Other available methods for RAD, as quick as FISH are QF-PCR [2,3] and MLPA [4]. Sparks et al [12] reviewed these other available RAD tests.…”

“…It does not require tissue cultures; results are quicker (2 days) and it is more cost effective. Keeping this in mind, RAD tests like FISH, quantitative fluorescence polymerase chain reaction (QF-PCR) [2,3] or multiplex ligation-dependent probe amplification (MLPA) [4] are often preferred for faster results.…”

Genetic polymorphisms of loci D18S53, D18S59, and D18S488 in fetuses from a Chinese Tianjin Han population

“…Hills et al (2010) retrospectively analyzed 737 prenatal diagnostic specimens in region 9 of London, and found that 73 cases with serious maternal contamination could be analyzed by QF-PCR alone. Compared with conventional cytogenetic prenatal diagnosis, QF-PCR has the advantages of being faster, more convenient, and cost-effective when applied to prenatal diagnosis (Jenderny et al, 2014).…”