Array CGH in routine prenatal diagnosis practice

Microarrays in prenatal diagnosis

In prenatal diagnosis, chromosomal microarray (CMA) has not yet fully replaced conventional karyotyping but has rapidly become the recommended test in pregnancies with ultrasound abnormalities. In this review, we provide an overview of the published data concerning this technology and the controversies concerning its use in the prenatal setting. There is abundant evidence indicating the added detection of pathogenic abnormalities with CMA in comparison to the traditional karyotyping, especially in fetuses with multiple or isolated ultrasound abnormalities such as congenital heart disease, increased nuchal translucency, or oral cleft. On the other hand, there is also a risk to detect variants of unknown significance, late-onset disorders, and variants in susceptibility loci. However, it has been shown that pregnant couples tend to prefer a maximum of information about the health of their unborn child. Taken together, CMA has considerable diagnostic and prognostic values during pregnancy and should therefore be the test of choice.

What results to disclose, when, and who decides? Healthcare professionals' views on prenatal chromosomal microarray analysis

Objectives

This study explored the views of healthcare professionals (HCPs) in the UK about what information should be disclosed, when; and whether women/parents should be given a choice as to what they wish to know.

Methods

Q‐methodology was used to assess the views of 40 HCPs (genetic HCPs, fetal medicine experts, lab‐scientists).

Results

Most participants agreed that variants of unknown clinical significance should not be disclosed. Participants were divided between those who considered variants of uncertain clinical significance helpful for parents and clinicians, and those who considered them harmful. Although recognising the potential disadvantages of disclosing risks for adult‐onset conditions, participants thought it would be difficult to withhold such information once identified. Participants largely supported some parental involvement in determining which results should be returned. Most participants believed that information obtained via CMA testing in pregnancy should either be disclosed during pregnancy, or not at all.

Conclusion

HCPs taking part in the study largely believed that variants that will inform the management of the pregnancy, or are relevant to other family members, should be reported. Recent UK guidelines, published after this research was completed, reflect these opinions. © 2016 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd.

What's already known about this topic?

Empirical data on healthcare professionals' (HCPs) and parents' experience with prenatal CMA are scarce.

Published data mainly focused on issues around uncertain results obtained via CMA, and on genetic health professionals.

The two main difficulties expressed by genetic counsellors associated with testing were interpreting uncertain results, and termination of pregnancies based on uncertain results

What does this study add?

It is the first study examining attitudes of a wide range of professionals involved in CMA testing: laboratory professionals, fetal medicine experts, and genetic health professionals.

We describe what types of results professionals think should or should not be disclosed and with whom they consider the onus for such decision making should lie.

These views are reflected in the recent UK guidelines about CMA testing.

Microarrays as a diagnostic tool in prenatal screening strategies: ethical reflection

Genomic microarray analysis is increasingly being applied as a prenatal diagnostic tool. Microarrays enable searching the genome at a higher resolution and with higher sensitivity than conventional karyotyping for identifying clinically significant chromosomal abnormalities. As yet, no clear guidelines exist on whether microarrays should be applied prenatally for all indications or only in selected cases such as ultrasound abnormalities, whether a targeted or genome-wide array should be used, and what these should include exactly. In this paper, we present some ethical considerations on the prenatal use of microarrays. There is a strong consensus, at least in Western countries, that the aim of prenatal screening for foetal abnormalities should be understood as facilitating autonomous reproductive choice for prospective parents. The tests offered should be valid and useful to reach that purpose. Against this background, we address several ethical issues raised by the prenatal application of microarrays. First, we argue that the general distinction between a targeted and a genome-wide microarray needs to be scrutinised. Then we examine whether microarrays are 'suitable tests' to serve either a screening or a diagnostic purpose. Given the wide range of findings possibly generated by microarrays, the question arises whether microarrays actually promote or interfere with autonomous reproductive decision-making. Moreover, if variants of unknown clinical significance are identified, this adds to the burden and complexity of reproductive decision-making. We suggest a qualified use of microarrays in the prenatal context.