Application of three-dimensional fluorescence in situ hybridization to human preimplantation genetic diagnosis

ObjectiveTo report a simple and efficient fluorescence in situ hybridization (FISH) method for preimplantation genetic diagnosis (PGD).DesignTechnique and method.SettingA hospital in vitro fertilization (IVF) laboratory.Patient(s)Women undergoing IVF or intracytoplasmic sperm injection (ICSI).Intervention(s)None.Main Outcome Measure(s)The intensity and clarity of signals, technical difficulty, the percentage of successfully treated blastomeres, and blastomere integrity after FISH.Result(s)This paraformaldehyde fixation technique simplified the process of fixation of blastomeres for PGD without losing blastomeres during fixation. A total of 35 blastomeres derived from 10 arrested embryos or abnormally fertilized eggs (one pronucleus or three pronuclei) were used for three-dimensional (3D) FISH staining. Signals in all blastomeres were obtained successfully by this method. Approximately 0.1 μL of DNA probe was enough for the detection of the signals in each blastomere, less than the volume (1 μL) used in the conventional FISH.Conclusion(s)The 3D-FISH technique for PGD is easy to learn, less damaging to blastomeres, and loses no blastomeres during fixation. It is efficient, feasible, and economic, which allows more patients to benefit from this technique.