Editors' ChoicePrenatal Testing

Finding a Needle in a Haystack

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Science Translational Medicine  10 Aug 2011:
Vol. 3, Issue 95, pp. 95ec125
DOI: 10.1126/scitranslmed.3002997

Genetic and genomic technologies are becoming increasingly integrated into prenatal care and are changing the kind of information that physicians and pregnant women can access about the fetus in utero. Fluorescence in situ hybridization (FISH) is currently used for cytogenetic analysis of fetal cells obtained through prenatal diagnostic tests such as amniocentesis or chorionic villus sampling. However, although this is a useful technique for identifying deviations from the normal 23 pairs of chromosomes, it cannot detect microdeletions or other small aberrations in the fetal DNA. Microarray-based assays can detect these smaller chromosomal abnormalities, but the data they yield is often difficult to interpret, and therefore they are not currently in widespread clinical use. Now, Shaffer et al. have developed a rapid prenatal microarray test for pregnancies predicted to be at low risk that can efficiently detect a specific set of clinically relevant abnormalities in fetal DNA.

Schaffer and colleagues selected 15 chromosomal microdeletions that may not be evident on fetal ultrasound but are clinically important and five common chromosomal aneuploidies for further testing. They developed an array-based multiplex assay to detect these abnormalities and screened 430 fetal cell samples collected from diagnostic tests, peripheral blood samples, or products of conception. They also developed specific software to analyze the data so that only clinically relevant microdeletions were detected. They report that their assay identified all but one chromosomal microdeletion in the 430 samples screened, suggesting that this assay may be a useful additional test to combine with standard cytogenetic analysis. This study marks a step forward in helping pregnant women access more information about their pregnancy and the health of their fetus. As the latest technologies continue to improve prenatal genetic testing, it will be equally important to concurrently develop mechanisms to help pregnant women and their partners make informed choices based on this information.

L. G. Shaffer et al., The development of a rapid assay for prenatal testing of common aneuploidies and microdeletion syndromes. Prenat. Diagn. 31, 778–787 (2011). [PubMed]

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