Dexeus Mujer extends its genetic screening to gamete donor programmes
According to the results of a study conducted on a sample of 2,403 individuals who took part in the Dexeus Mujer egg donor programme between January 2014 and January 2018, presented by Dr Anna Veiga - Director of R&D&i of the Reproductive Medicine Unit of Dexeus Mujer - at the latest Meeting of the European Society of Human Reproduction and Embryology (ESHRE), 2.7% of previous donor allocations in egg donor programmes risk transmitting to the foetus some form of hereditary disease caused by recessive genetic mutations. This has led the Genomic Medicine Unit of Dexeus Mujer to expand the genetic screening that it routinely carries out as part of its egg donor programme to gamete donors, following the recommendations of the American College of Medical Genetics (ACMG).
This screening uses the qCarrier test, developed by Dexeus Mujer with qGenomics, and can detect 200 genes associated with 314 monogenic disorders (277 autosomal recessive mutations and 37 associated with the X chromosome).
In general, the likelihood of a couple transmitting a hereditary disease caused by a recessive mutation to their children is 1-2%, since it would require both partners to be carriers of the same mutation. The surprising fact, though, is that more than 50% of the population are carriers of this type of mutation but do not know it because the disease does not manifest itself. This is due to the fact that the disease is linked to recessive genes, meaning that both partners must be carriers of the same disorder.
Of the 2,403 individuals tested in the study, 1,015 (42.2%) were egg donors and 1,388 (57.8%) were the male partners of egg recipients. Allocation was carried out by arranging a prior visit with advice and genetic counselling, both with the couples and the donors. The results showed that 1.9% of donors were carriers of an abnormality linked to the X-chromosome and so were ruled out as donors, and 8.2% had a family history of genetic disease. Furthermore, 60.6% of the tested population were carriers of at least one (or more) genetic disorder associated with a disease.
The authors conclude that it is essential for all patients and donors involved in egg donation programmes to have a prior genetic counselling visit (at Dexeus Mujer, this happens in 80% of cases) and undergo a screening test, since these two measures have been found to contribute significantly to detecting possible risks and reducing the transmission of possible hereditary diseases to future babies.
Genetic carrier screening in gamete donor programs
Anna Veiga, Anna Abulí, Gabriela Palacios.
Reproductive Medicine Service, Dexeus Mujer, Barcelona.
Presentation ESHRE 2018