First systematic experience of preimplantation genetic diagnosis for de-novo mutations.

Standard preimplantation genetic diagnosis (PGD) cannot be applied for de-novo mutations (DNM), because neither origin nor relevant haplotypes are available for testing in single cells. PGD strategies were developed for 80 families with 38 genetic disorders, determined by 33 dominant, three recessive and two X-linked DNM. All three recessive mutations were of paternal origin, while of 93 dominant mutations, 40 were paternal, 46 maternal and seven detected in affected children. The development of specific PGD strategy for each couple involved DNA analysis of the parents and affected children prior to PGD, including a mutation verification, polymorphic marker evaluation, whole and single sperm testing to establish the normal and mutant haplotypes and PGD by polar body analysis and/or embryo biopsy. Overall, 151 PGD cycles were performed for 80 families, for which a specific PGD design has been established. The application of these protocols resulted in pre-selection and transfer of 219 (1.72 per cycle) DNM-free embryos in 127 (84.1%) PGD cycles, yielding 63 (49.6%) unaffected pregnancies and birth of 59 (46.5%) healthy children, confirmed to be free of DNM. The data show feasibility of PGD for DNM, which may routinely be performed with accuracy of over 99%, using the established PGD strategy.

Preimplantation genetic diagnosis for hemoglobinopathies.

Hemoglobinopathies are the most frequent indications for preimplantation genetic diagnosis (PGD), allowing couples at-risk of bearing offspring with thalassemia and sickle cell disease to reproduce without fear of having an affected child. The present experience includes PGD for sickle cell disease, α- and ß-thalassemia (α- and ß-thal). We present here the results of the world's largest experience of over 395 PGD cycles for hemoglobin (Hb) disorders, resulting in the birth of 98 healthy, hemoglobinopathy-free children, with seven pregnancies still ongoing. One-third of these cases were performed in combination with HLA typing, allowing the birth of unaffected children who were also HLA identical to the affected siblings with hemoglobinopathies in these families, with successful or pending stem cell transplantation in a dozen of them. The results show that PGD is presently a practical approach for prevention of hemoglobinopathies, gradually also becoming a useful approach to improving access to HLA-compatible stem cell transplantation for this group of diseases.

First systematic experience of preimplantation genetic diagnosis for single-gene disorders, and/or preimplantation human leukocyte antigen typing, combined with 24-chromosome aneuploidy testing.

OBJECTIVE: To study the feasibility, accuracy, and reproductive outcome of 24-chromosome aneuploidy testing (24-AT), combined with preimplantation genetic diagnosis (PGD) for single-gene disorders (SGDs) or human leukocyte antigen (HLA) typing in the same biopsy sample. DESIGN: Retrospective study. SETTING: Preimplantation genetic diagnosis center. PATIENT(S): A total of 238 PGD patients, average age 36.8 years, for whom 317 combined PGD cycles were performed, involving 105 different conditions, with or without HLA typing. INTERVENTION(S): Whole-genome amplification product, obtained in 24-AT, was used for PGD and/or HLA typing in the same blastomere or blastocyst biopsy samples. MAIN OUTCOME MEASURE(S): Proportion of the embryos suitable for transfer detected in these blastomere or blastocyst samples, and the resulting pregnancy and spontaneous abortion rates. RESULT(S): Embryos suitable for transfer were detected in 42% blastocyst and 25.1% blastomere samples, with a total of 280 unaffected, HLA-matched euploid embryos detected for transfer in 212 cycles (1.3 embryos per transfer), resulting in 145 (68.4%) unaffected pregnancies and birth of 149 healthy, HLA-matched children. This outcome is significantly different from that of our 2,064 PGD cycle series without concomitant 24-AT, including improved pregnancy (68.4% vs. 45.4%) and 3-fold spontaneous abortion reduction (5.5% vs. 15%) rates. CONCLUSION(S): The introduced combined approach is a potential universal PGD test, which in addition to achieving extremely high diagnostic accuracy, significantly improves reproductive outcomes of PGD for SGDs and HLA typing in patients of advanced reproductive age.