Carrier Screening & Preimplantation Genetic Diagnosis (PGD)
It is now recommended to offer genetic screening to all couples considering pregnancy. In this circumstance, genetic screening refers to looking for mutations that couples may carry that together could give rise to a child with a genetic disorder. These types of disorders require the child to inherit two copies of the gene, one from their mother and one from their father. By testing for these types of genes before pregnancy we can identify couples who may be at risk for having a child affected by one of these disorders.
If a couple is found to be at risk for a genetic disorder, this usually means that both the male and the female carry a genetic mutation that will only cause a disease if the child inherits the gene from both mother and father. Armed with the knowledge about the mutation and using the advanced technologies available to us, we can now nearly eliminate the possibility of having a child affected by that genetic disorder. Working together with our colleagues at genetic laboratories, we would develop probes to the specific gene in question. Then by performing IVF, the embryos are biopsied and a few cells from each embryo are sent to the genetics laboratory. The probe is then used to identify which embryos are not affected by the gene and therefore should be used for transfer. This technique, called Preimplantation Genetic Diagnosis (PGD) has been used to prevent hundreds of different genetic disorders.