ABSTRACT

Preimplantation genetic testing (PGT) has evolved into a well-established alternative to invasive prenatal diagnosis despite the fact that genetic testing of single or few cells is quite challenging. PGT-M is in theory available for any monogenic disorder for which the disease-causing locus has been unequivocally identified. In practice, the list of indications for which PGT is allowed may vary substantially from country to country, depending on PGT regulation. Technically, the switch from multiplex PCR to robust generic workflows with whole-genome amplification followed by SNP array or NGS represents a major improvement: the waiting time for the couples has been substantially reduced since the customized preclinical workup can be omitted and the workload for the laboratories has decreased. Another evolution is that the generic methods now allow for concurrent analysis of PGT-M and PGT-A. As innovative algorithms are being developed and the cost of sequencing continues to decline, the field of PGT moves forward to a sequencing-based, all-in-one solution for PGT-M, PGT-SR, and PGT-A. This will generate a vast amount of complex genetic data, for instance on disease susceptibility genes or on chromosomal mosaicism, entailing new challenges for genetic counseling. It is clear that the rapid technological advances in the field of PGT should be balanced with ethical reflection and thorough discussions.