Three years of PGS by NGS: a mature technique for embryo chromosome screening

In June 2013 the first baby resulting from a NGS-PGS screened IVF cycle was born in Pennsylvania, USA. Since this initial approach for the application of NGS to PGS, methodologies have been further streamlined by NGS technology firms and a few highly specialized PGS labs.

This anniversary occurs just before the upcoming Annual Meeting of the European Society of Human Reproduction and Embryology (ESHRE, Helsinki 3-6 July) where the latest technical developments and clinical outcomes in this field are reviewed.

In this context a significant pioneer experience will be presented by the cooperation of Bioarray genetic lab and IVF-Spain fertility clinic in Alicante, Spain. Since Bioarray developed, validated and released PGS by NGS in 2014, this alliance has provided PGS to more than hundred European couples, with the first NGS-screened baby born in September 2015. To date an overall of 64 born babies and 53 ongoing pregnancies have been achieved.

The emergence of NGS technology meant unprecedented high-throughput gene sequencing —i.e. determining the order of nucleotides in a DNA strand— for research and diagnosis in Medical Genetics, with the detection of disease-causing point mutations as perhaps the most palpable clinical benefit. But also NGS has been revealed as an exceptional and affordable way to check embryo chromosomal status starting from only one or a few cells, available through biopsy procedures at IVF labs.

Due to this very “gene-sequencing“ nature, NGS offers unique versatility not available with previous PGS technologies like CGH. Accordingly the partnership in Alicante also provided PGD+PGS by NGS to a number of couples carrying a single-gene disorder, who had their embryos checked to prevent the disease being passed to their children, by means of Bioarray’s integrated PGD setup (linkage analysis) + PGD + PGS in a single fast robust NGS workflow.