Preimplantation genetic testing for monogenic disorders

Couples who are carriers of genetic disorders, including recessive or dominant single gene defects or sex-linked conditions, face a reproductive risk. For patients at risk of passing on a dominant disorder to their children, natural conception usually carries a 50% chance with each pregnancy that the fetus will be affected by the disease. Couples where both parents are carriers of a recessive disorder generally face a 25% chance with each pregnancy of having an affected child.

Preimplantation genetic diagnosis (PGT-M) significantly reduce a couple’s risk of transmitting a genetic disorder by diagnosing a specific genetic disease in oocytes or early human embryos that have been cultured in vitro, before a clinical pregnancy has been established.

Since PGT-M is performed on single or a few cells, the genetic analysis technique has to be adapted and pushed to its physical limits. This implies first the design and development of the PGT-M strategy, followed by a process of fine-tuning of the analysis conditions on single cells, in order to optimize and validate the PGT-M protocol before its clinical application. This phase is known as “pre-clinical PGT-M work-up”.

The pre-clinical PGT-M work-up includes blood sample and/or cheek cells analysis of the prospective parents for mutation verification and informativeness testing for the polymorphic markers included in each assay.

Almost all genetically inherited conditions that are diagnosed in the prenatally can also be detected by PGT-M. Generally, it is possible to perform PGT-M for any genetic disorders, autosomal dominant, recessive or X-linked, with an identifiable gene.