Several months back, we reported in our blog that the authorities that regulate IVF and other fertility procedures in the UK were considering allowing IVF with mitochondrial transfer to move forward. Mitochondrial transfer is more popularly known as “three parent IVF,” because it involves three genetic parents: the woman who provides her chromosomes, the husband who provides his chromosomes and the donor who provides the mitochondria which contain their own DNA. The HFEA in the UK has now given the green light for tightly regulated research to proceed on mitochondrial transfer. So, now it is likely that fertility researchers in Britain will move forward and learn whether this technique can help couples with mitochondrial diseases.
The use of Preimplantation Genetic Testing (PGD) enables fertility doctors to screen embryos for genetic diseases such as Cystic Fibrosis or Sickle Cell Anemia, permitting couples at high risk to avoid transmitting these diseases onto their children. PGD is done as part of an IVF cycle. A biopsy is taken when the embryo reaches the 8 cell or the blastocyst stage, and tested for the specific gene we are concerned about. This same technology can also be used to test for genes that do not necessarily cause a disease but put an individual at risk for other serious diseases. One such genetic mutation, called the BRCA 1 and 2 gene, puts affected women at very high risk for developing breast and ovarian cancer. The risk of developing these cancers in affected women is so high that many women (such as Angelina Jolie) chose to have their breasts and/or ovaries surgically removed just to prevent cancer. Since we know the genetic sequence of the BRCA mutation, it is possible to screen embryos for it, and prevent transmitting the gene onto one’s daughters. This article in the Wall Street Journal tells the story of a family who decided to go that route.
This article which appeared recently in our local paper The Trenton Times (and originaly in the Star Ledger) profiled a laboratory we work with at Princeton IVF called Reprogenetics. The test they discussed called Array cGH involves removing some cells from embryos created during IVF and testing them to compare the amount of genetic material they contain from each of the chromosomes. It enables us to diagnose disorders such as Down Syndrome and Turner Syndrome, avoid putting back most abnormal embryos and select embryos for gender. In comparison to earlier methods it is a more comprehensive chromosome screening technique. Click here to read the article.