Preimplantation Genetic Diagnosis for the Better Management of Couples During Assisted Reproduction

Intracytoplasmic Sperm Injection (ICSI) of- fers the real prospect of genetic parenthood for men with profound oligozoospermia and azoospermia. However, it may result in transgenerational transmission of genetic de- fect, which substantially increases the recurrence risk of infertility in the offspring of couples treated with ICSI. Re- cent developments in the field of genetics and assisted re- production have led to emergence of preimplantation ge- netic diagnosis (PGD). PGD helps in the negative selection of the aneuploid and abnormal embryos. For PGD, the em- bryo is biopsied and 1-2 blastomeres are removed from the 6-10 cell embryo. For establishing the diagnosis, the ge- netic analysis is carried out using FISH (for structural and numerical chromosomal anomalies) or PCR (for single gene disorders). Only the normal embryos are transferred back to the uterus, thus ensuring a normal pregnancy. Spare or arrested embryos obtained following ICSI were used for the study. FISH was performed on 5 embryos using CEP X spectrum green probes. PCR was done for cystic fibrosis common mutation ∆ F508 and for β-thalassaemia IVS1→ 5 and 619 bp deletion using blood as positive control. Mosa- icism was noted in two of the five embryos using FISH. The blastomeres were found to be normal for cystic fibro- sis and β-thalassaemia. PGD has an important role in help- ing patients to avoid the risk of transmission of genetic de- fect or abnormalities and also helps in avoiding repeated medical termination of pregnancy.