Chromosome analysis is often performed on parents who have a history of miscarriages or a child with a chromosome abnormality. Sometimes, one partner is found to be a carrier of a chromosome translocation. A chromosome translocation is the result of pieces of two chromosomes that have broken off and switched places; it is “balanced” because there is no extra or missing chromosome material.
All of the chromosome material is still present in an individual with a balanced translocation. A carrier, however, has a significant increased risk of repeated miscarriages or a child with a serious chromosome problem. The goal of preimplantation genetic diagnosis (PGD) for chromosome translocation carriers is to reduce the number of pregnancy losses and reduce the number of affected offspring.