Reproductive Genetics: Fetal karyotyping: what should we be offering and how?

In the context of developing prenatal diagnosis (PND) service delivery models, there is no doubt that the most significant innovation will come from the application of a technology known as array comparative genomic hybridisation (aCGH), which in some postnatal clinical scenarios will soon replace conventional karyotyping as the front-line 'whole-genome test'. There are a number of scenarios that may provide drivers for the adoption of aCGH as the first-line whole-genome test following invasive PND, of which the following two appear the most probable: cases that, following invasive PND, are reported to be normal following quantitative fluorescence polymerase chain reaction (QF-PCR) and/or karyotyping but have abnormal ultrasound findings; and cases that are normal following non-invasive PND (NIPD) for the autosomal aneuploidies but have abnormal ultrasound findings (first trimester or at the 18-20 week anomaly scan).