Preimplantation genetic diagnosis using fluorescent polymerase chain reaction: Results and future developments

Purpose: Fluorescent polymerase chain reaction (PCR) is a multipurpose tech nique that can be used for diagnosing sex, single-gene defects, and trisomi es as well as determining DNA fingerprints from single cells. However its e ffectiveness must be assessed before clinical preimplantation genetic diagn osis (PGD) application. Methods: Single and multiplex fluorescent PCR was applied to single cells a nd blastomeres. Results: Fluorescent PCR can be used to diagnose sex from blastomeres and h as been successfully applied in a clinical PGD sexing program resulting in a confirmed pregnancy. A further major advantage of fluorescent PCR is the ability to multiplex, providing multiple diagnoses and DNA fingerprints wit h a high reliability (similar to 75% for trisomy, 86% for DNA fingerprint) and good accuracy (70-80%). Allele drop-out in multiplex PCR is similar to 20% per allele and does not appear to be associated with the fragment size. Conclusions: Fluorescent PCR is a powerful technique for PCD, and the effec ts of allele dropout must be considered, particularly in multiplex PCR.