ABSTRACT
There are various approaches for preimplantation genetic diagnosis (PGD), but in essence all share the same principal aim-to allow healthy embryos to be distinguished from those affected by genetic abnormalities. Depending on the exact protocol used, inherited mutations affecting the function of specifi c genes or abnormalities of chromosome copy number can be detected. The preferential transfer of genetically “normal” embryos to the uterus provides a high probability that any resulting pregnancy will be healthy. In some respects PGD can be considered an alternative to conventional prenatal diagnosis, with the advantage that pregnancy termination is avoided.
