Day 1 started with a presentation on the technical aspects embryo biopsy (Gaia Terzuoli, on behalf of Cristina Magli) and the potential of non-invasive methods, while Francesco Fiorentino provided an update on diagnostic methods following biopsy. The day continued with two much anticipated talks on PGT-A. First, Karen Sermon reviewed recent trials in PGT-A and particularly the implications of secondary outcomes (fewer interventions and miscarriages, shorter time to pregnancy) and raised questions on cost, detection of mosaic embryos and potential damage to the embryo. Carmen Rubio presented data suggesting that female age but not oocyte number has impact on embryo aneuploidy rate, which vitrification does not increase.
On day 2 Andres Salumets discussed the use of genotyping to predict reproductive ageing, emphasising the role of synaptonemal complex, DNA damage response or meiosis genes. He then raised the issue of chromosomal instability influencing human reproduction. There was discussion over data showing that aneuploid cells are eliminated during pregnancy but some mosaicism persists at tissue level. Following this, Ivanka DImova reported that a BRCA1/BRCA2 mutation is the major predisposing factor for breast cancer. Establishing a molecular diagnosis is thus required to quantify cancer risk and oncogenetic counseling is essential both pre- and post-testing.
Anja Pinborg evaluated studies on the health of children after ART and PGT. The most important risk factor remains multiple pregnancy, she said. Some adverse ART effects were noted (relating to perinatal outcomes and congenital abnormalities), although more data is required to properly evaluate others (eg, metabolic, cardiovascular). No increased risk for cancer or neurodevelopmental disorders has been detected. Results for PGT-children are rather reassuring, though long-term data are also not available.
Elpida Fragouli discussed secondary findings from her work with aCGH and NGS. She proposed that guidelines for PGT-A need re-evaluation for the transfer of mosaics (always followed-up with prenatal diagnosis). However, she emphasised that complex mosaics and monosomic or trisomic mosaics should always be avoided. Claudia Spits continued on the subject of aneuploidy and mosaicism, which appear to decrease in prevalence as we move from the cleavage to the blastocyst stage. Joyce Harper described how preconception, preimplantation and prenatal genetic testing have evolved over the years, adding yet unpublished data on expanded carrier screening panels (how few genes are common between them) and ending on the topic of genome editing. Questions on the future availability of these tests to the general public remain. Martina Witsch-Baumgartner discussed the interpretation of genetic variants, their classification, use of databases and in-silico prediction programmes. The day closed with Alexey Savov setting out the current status of newborn screening in Southeastern Europe, urging an improvement in phenylketonuria screening and future priorities for neonatal screening overall.
Day 3 opened with a very informative presentation by Faustina Lalatta on genetic counseling for infertile couples and the need for a multidisciplinary approach. Joanna Poulton presented approaches for preventing transmission of mitochondrial disease (oocyte donation, PND, PGD, mitochondrial replacement therapy), while Rita Vassena reviewed the promise and risks of genome editing in germ cells and human embryos, emphasising safety before any clinical use. During the course we also had two junior research sessions with presentation of selected submitted abstracts by Luis Alcaraz, Omid Faridani and Leyla Sati.

Georgia Kakourou
Co-ordinator SIG Reproductive Genetics