PGD for Chromosomal Rearrangements
Chromosomal rearrangements such as reciprocal/Robertsonian translocations and pericentric and paracentric inversions are well-recognized forms of genetic abnormality. Preimplantation genetic diagnosis can be used to detect chromosomal rearrangements in embryos with the aim of transferring only normal/balanced ones for the establishment of a healthy pregnancy. A large number of cases has been carried out since the first clinical application of PGD for chromosomal rearrangements. Different studies reporting on the outcome of PGD cases for translocation carriers have demonstrated an increase in the chances of sustaining a pregnancy to full term: 85% of pregnancies on average were lost before PGD, while only 0-25% miscarried after PGD. Furthermore, PGD reduces the time needed for carriers of structural chromosome abnormalities to achieve a sustained pregnancy. Studies have shown that patients undergoing PGD achieve pregnancy in an average of 1.2-1.4 IVF cycles (<4 months) while patients without PGD require a much longer interval (mean 4-6 years). Reprogenetics offers PGD for a wide range of chromosomal rearrangements (including Robertsonian and reciprocal translocations and inversions) through utilization of array comparative genomic hybridization (aCGH) and fluorescence in situ hybridization (FISH) technologies.