Birth of healthy children after preimplantation diagnosis of thalassemias

Background: Preimplantation genetic diagnosis (PGD) allows couples at risk of having children with thalassemia to ensure the healthy outcome of their pregnancy. Methods: Seventeen PGD clinical cycles were initiated for Cypriot couples a t risk of having children with different thalassemia mutations, including I VSI-110, IVSI-6, and IVS II-745. Unaffected embryos for transfer were selec ted by testing oocytes, using first and second polar body (PB) removal and nested polymerase chain reaction analysis followed by restriction digestion . Results: Unaffected embryos were selected in 16 of 17 PGD cycles. Of 166 oo cytes studied from these cycles, 110 were analyzed by sequential analysis o f both the first and the second PB, resulting in preselection and transfer of 45 unaffected embryos. This resulted in seven pregnancies and in the bir th of five healthy thalassemia-free children. The embryos predicted to have inherited the affected allele were not transferred. Analysis of these embr yos confirmed the PB diagnosis. Conclusions: Sequential first and second PB testing of oocytes is reliable for PGD of thalassemia and is a feasible alternative to prenatal diagnosis in high-risk populations.