Preimplantation genetic diagnosis by fluorescence in situ hybridization: clinical possibilities and pitfalls.

Preimplantation genetic diagnosis using the fluorescence in situ hybridization technique (FISH) is being used widely to prevent the transmission of sex-linked diseases, to screen for translocations, and for aneuploidy screening in specific in vitro fertilization (IVF) patient groups, along with FISH analysis of spermatozoa in infertile men. In this study, we aim to critically analyze our clinical results in patients at risk of transmitting sex-linked diseases (n = 55), in carriers of translocations (n = 43), in women who have recurrent miscarriage (two or more miscarriages) (n = 128), recurrent IVF failure (three or more failed IVF attempts) (n = 47), and patients of advanced maternal age (37 years old or older) (n = 79). The use of the FISH technique in carriers of sex-linked diseases and translocation patients prevents transmission of these conditions and provides good IVF outcome. In patients with recurrent miscarriage, implantation failure, and advanced maternal age, a high incidence of embryos with abnormal chromosomes 13,16,18,21,22, X, and Y was observed (range 69-75%), as expected. In those three groups of patients, the selection of euploid embryos for transfer resulted in good pregnancy rates with a low incidence of miscarriage. Limitations and pitfalls of this technique are also discussed.