PGD is recommended primarily in the following cases (Sermon K. et al, 2004):
- Monogenically transmitted diseases: In this category, currently only sex-linked diseases can be tested in Hungary by sexing. Screening for other monogenetic diseases by PGD is expected in the near future.
- Chromosomal disorders:
- – In parents carrying a balanced translocation, generally detected as a result of tests related to spontaneous miscarriage, infertility, or when a previous conception resulted in an unbalanced translocation.
- – Aneuploidy, or numerical chromosomal abnormalities that are generally detected by infertility tests.
- Pre-implantation genetic screening (PGS): Primary candidates include women of advanced maternal age or repeated IVF-ET failure. However, this procedure is currently at the stage of trial and therefore it is currently not supported in Hungary.
- HLA matching: This indication is currently not supported and cannot be administered in Hungary.
Intracytoplasmic sperm injection (ICSI)
ICSI is a micromanipulation in vitro fertilization technique, where a single sperm is injected directly in the cytoplasm of an egg. It is most commonly used where sperms are unable to fertilize the egg (due, for instance, to low sperm count, poor motility, etc.). When PGD is carried out ICSI is generally used for fertilization to avoid a false test result caused by the genome of residual sperm adhered to the zona pellucida.