Five Years of Experience in Preimplantation Genetic Diagnosis for Single Gene Diorders: Royan Report

Background: Preimplantation genetic diagnosis (PGD) has been practiced in those couples who are affected/carrier to the single gene disorders (SGD) wishing to have a normal baby since 1987. It is the golden standard method in those with fertil-ity problems or affected to SGDs in which the legal permission for induced abortion is not allowed. In Iran, due to popularity of consanguine marriages, carrier status to the SGDs is frequent especially for thalassemia which has a high incidence in some provinces. Therefore, PGD will be highly applicable in men-tioned couples who are usually reluctant to induced abortion following prenatal diagnosis. Here, we report our experience in carrying out PGD for single gene disorders for couples referred to Royan infertility center from June, 2014 till March 2019.Materials and Methods: Couples underwent assisted repro-ductive treatment following standard protocols. Single blasto-mere biopsies were done on third day in embryology laboratory and embryo transfers achieved on 5th day. 125 indications from various SGDs were assessed for informative short tandem re-peats and mutation confirmation in a preliminary step for each family to be able to determine the pattern of segregation of link-age markers. On PGD day, the genotype of each embryo was detected based on direct mutation analysis (if applicable for the particular SGD) and confirmed by analysis of the pattern of in-herited linkage markers.Results: In total 302 cycles of PGD including 156 for beta thalassemia were done in which 1918 embryos were assessed for SGD status including 992 for beta thalassemia. Among them, 751 embryos were diagnosed as unaffected and selected for transfers including 437 for beta thalassemia, of them, 347 embryos were transferred including 204 for beta thalassemia disease. Pregnancy (chemical/clinical) was achieved in 80 couples (28.2% per ET) including 40 (26.4% per ET) in beta thalassemic couples. Positive outcome (take home baby) was reported in 46 (16.2% per ET) and 28 (17.9% per ET) for beta thalassemic couples. We also detected the rates of allele drop out, contamination and no amplification as 4.7%, 1.4% and 9.8% in respect.Conclusion: PGD for single gene disorders is an attractive option for carrier/affected couples and may be the only one in those with infertility problems.