Preimplantation genetic diagnosis of DiGeorge syndrome

We report the first case of preimplantation genetic diagnosis used in orderto avoid chromosomal imbalance in the progeny of a woman mildly affected byDiGeorge syndrome and carrier of a microdeletion of chromosome 22q11.2. Intotal, seven embryos were biopsied in three separate treatments andanalysed by fluorescent in-situ hybridization (FISH). Of these, four werecarrying the deletion, two were normal and in one the analysis wasinconclusive. The diagnostic procedure was performed within 5 h. Thisallowed the biopsied embryos to be transferred the same day as the biopsywas taken (day 3). Two embryos were transferred in the third treatment, butno pregnancy was established. Patients with a 22q11 microdeletion, who havea 50% risk of transmitting the deletion to their offspring, can now beoffered preimplantation genetic diagnosis using FISH for the detection of a22q11 deletion.