Tuesday, August 29, 2017

Preimplantation Genetic Diagnosis

Did you know that Neurofibromatosis is an autosomal dominant genetic condition? That means that people with Neurofibromatosis have a 50% chance of passing it along to their children. Dominant inheritance means that only one abnormal gene from a parent is needed to cause disease. This happens even when the matching gene from the other parent is completely normal and healthy. The abnormal gene "dominates" the normal one.

Pregnancy can be a scary time for families, especially when there is a risk of passing along a genetic condition to offspring. Neurofibromatosis is an extremely variable condition, and just because one person in the family has a mild case, does not mean that their offspring will have the same manifestations. One case may be mild, one severe, the next barely noticeable. One family member may suffer with learning disabilities, the others may not. Some may suffer with relentless chronic pain, others will deal with persistent feelings of numbness and tingling in their extremities...

When it comes time to having children, couples who have known cases of NF should be seen by a genetics counselor. A genetics counselor will assess risks associated with pregnancy, and will offer different kinds of services to help with maternal well-being. One relatively new "service" that is available to couples is preimplantation genetic diagnosis.

Preimplanation genetic diagnosis is a technique used to detect genetic "defects" within embryos prior to implantation. This can not only be used for couples who have known  chromosomal disorders (ex: NF), but also for couples with sex linked conditions (ex: hemophilia), carriers of single gene disorders (ex: cystic fibrosis) and women who have had recurrent pregnancy loss.  

This process is done in conjunction with  in vitro fertilization, and is a little bit tedious. So here's how it's done: 

1. Egg retrieval and fertilization occurs in a laboratory 

2. Five days after the embryos are developed, several cells are microsurgically removed from the embryos. The DNA of the cells is tested to see whether or not the "problematic" gene is present in the embryo. 

3. Once "healthy" embryos are discovered, they are implanted into the uterus through the process of in vitro fertilization. 

Sounds pretty simple, right?! Well this process can be pretty lengthy... it can take 4-6 weeks to complete one cycle of IVF. The genetic testing takes 1-2 weeks minimum. Then you have to take into consideration all the appointments you need to be scheduled for... it can take a while! Also, this procedure is relatively expensive. One round of IVF can cost $10,000 - $15,000 and then the genetic testing can tack on an extra $4,000 - $5,000... IVF is also not guaranteed to work and couples may need several rounds of treatment before they are successful. 

Now I tried finding some statistics for you all on how "guaranteed" this procedure is, and from the looks of it, it seems pretty darn reliable. Since only the unaffected embryos are implanted, you are pretty much guaranteed to avoid the gene you are trying to avoid. However, other genetic variances may still be passed onto your child... this technology does not prevent all genetic anomalies. 

This technology still remains relatively controversial in the medical community, and many people have many different opinions on the use of it. It has recently gained some traction in the media for allowing people to create the "perfect designer baby", but keep in mind that it can be used for MUCH more than that. 

- Court



  1. This is a most important issue for those wanting to have children. so it's a long drawn out procedure.

  2. Thank you for posting. I believe my child has NF, and before I share this with other family that are more sensitive to concerns (worries) I wanted to know what could happen.

    The news was looking pretty bad until I found your page. I guess thats the problem with internet diagnosis - it can give you the wrong information.

    1. The internet can be a scary place, especially when it comes to under-researched medical conditions! Please feel free to share this blog, and ask any questions you may have :)