Next generation sequencing is a highly reliable method to analyze exon 7 deletion of survival motor neuron 1 (SMN1) gene

Spinal muscular atrophy (SMA) is one of the most common and severe genetic diseases. SMA carrier screening is an effective way to identify couples at risk of having affected children. Next-generation sequencing (NGS)-based expanded carrier screening could detect SMN1 gene copy number without extra experiment and with high cost performance. However, its performance has not been fully evaluated. Here we conducted a systematic comparative study to evaluate the performance of three common methods. 478 samples were analyzed with multiplex ligation probe amplification (MLPA), real-time quantitative polymerase chain reaction (qPCR) and NGS, simultaneously. Taking MLPA-based results as the reference, for 0 copy, 1 copy and ≥ 2 copy SMN1 analysis with NGS, the sensitivity, specificity and precision were all 100%. Using qPCR method, the sensitivity was 100%, 97.52% and 94.30%, respectively; 98.63%, 95.48% and 100% for specificity; and 72.72%, 88.72% and 100% for precision. NGS repeatability was higher than that of qPCR. Moreover, among three methods, NGS had the lowest retest rate. Thus, NGS is a relatively more reliable method for SMN1 gene copy number detection. In expanded carrier screening, compared with the combination of multiple methods, NGS method could reduce the test cost and simplify the screening process.

Qualitative study of GPs’ views and experiences of population-based preconception expanded carrier screening in the Netherlands: bioethical perspectives

ObjectiveBetween 2016 and 2017, a population-based preconception expanded carrier screening (PECS) test was developed in the Netherlands during a pilot study. It was subsequently made possible in mid-2018 for couples to ask to have such a PECS test from specially trained general practitioners (GPs). Research has described GPs as crucial in offering PECS tests, but little is known about the GPs’ views on PECS and their experiences of providing this test. This article presents a thematic analysis of the PECS practice from the perspective of GPs and a bioethical discussion of the empirical results.DesignEmpirical bioethics. A thematic analysis of qualitative semi-structured interviews was conducted, and is combined with an ethical/philosophical discussion.SettingThe Netherlands.Participants7 Dutch GPs in the Netherlands, interviewed in 2019–2020.ResultsTwo themes were identified in the thematic analysis: ‘Choice and its complexity’ and ‘PECS as prompting existential concerns’. The empirical bioethics discussion showed that the first theme highlights that several areas coshape the complexity of choice on PECS, and the need for shared relational autonomous decision-making on these areas within the couple. The second theme highlights that it is not possible to analyse the existential issues raised by PECS solely on the level of the couple or family. A societal level must be included, since these levels affect each other. We refer to this as ‘entangled existential genetics’.ConclusionThe empirical bioethical analysis leads us to present two practical implications. These are: (1) training of GPs who are to offer PECS should cover shared relational autonomous decision-making within the couple and (2) more attention should be given to existential issues evoked by genetic considerations, also during the education of GPs and in bioethical discussions around PECS.