PGT-A: Preimplantation genetic testing for aneuploidy

This is an option that can be offered as part of in vitro fertility treatment, particularly for patients at a higher risk of embryo aneuploidy due to their age.

Ruling out aneuploidy by PGT-A prior to embryo transfer significantly increases the pregnancy rate for women aged over 35 (from 37% to 51%, according to a very recent randomised study: Fertil Steril 2019; 112:1071-1079.e7).

There may be other indications for PGT-A, such as repeated implantation failure in the course of assisted conception, frequent miscarriages or a history of aneuploidy in previous pregnancies.

PGT-SR: preimplantation genetic testing for structural rearrangements in chromosomes

The main indications for PGT-SR screening are reciprocal translocations, Robertsonian translocations, and inversions, affecting 0.16%, 0.1% and 0.02% of the general population, respectively (Reprod Biomed Online 2019; 38:S1, E3-E4). The pregnancy rate reported in the literature following PGT-SR is in the region of 45% (Prenat Diagn 2019; 39:866-870).

PGT-M: test for the presence/absence of a “monogenic” disease (M)

Monogenic diseases caused by mutations that are pathogenic (i.e. responsible for diseases), or are probably pathogenic and responsible for different types of transmission (autosomal dominant or autosomal recessive, X-linked diseases, mitochondrial diseases, etc.) may come into consideration for PGT-M.

The causal link between the mutation and the disease must be precisely established, repercussions on health must be significant and symptoms must be present from birth, childhood or adulthood (Hum Reprod Open. 2020 May 29;2020(3):hoaa021. doi: 10.1093/hropen/hoaa021).

An internal ethics committee assesses the validity of these criteria for all individual indications (link to CPMA). The pregnancy rate following PGT- M, described in the literature, is in the region of 50% (48.9%; Prenat Diagn 2019; 39:866-870).

Preimplantation test PGT-A, PGT-SR, PGT-M at Genesupport