66 - Preimplantation Genetic Diagnosis for Single-Gene Disorders

Summary

Although preimplantation genetic diagnosis (PGD) was first reported more than thirty years ago by Robert G. Edwards and his colleagues when they managed to identify the sex of rabbit blastocysts, it was not until later in the 1980s when PGD of human embryos was extensively investigated. In 1990, Alan Handyside reported the birth of healthy females after sex selection using polymerase chain reaction (PCR) to amplify a Y chromosome repeat sequence to exclude male embryos (1).

Further advancements in the arena of IVF, micromanipulation, and DNA technology led to remarkable progress in the field of PGD. It is now an established clinical option in reproductive medicine and has already helped couples all over the world to conceive healthy children. Based on the 186 responses from IVF centers in the United States to a survey by the Genetics and Public Policy Center at Johns Hopkins University in 2006, PGD was reported to be provided by nearly three-quarters of these IVF clinics and it is estimated that 4–6 percent of all their IVF cycles include PGD (2). Many international bodies have strived to come up with evidence-based protocols for the procedure, including the American Society of Reproductive Medicine, the European Society for Human Reproduction and Embryology, and the PGD International Society. In the absence of wide, randomized controlled trials, most of the recommendations that these international bodies came up with are considered general guidelines based on clinical experience and published data (3–8).