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Information contained in this site is strictly for education purpose to better understand the conditions associated with Williams Syndrome. You should in no way use this site for diagnosis, treatment or medical guidance. Always seek medical advice from your doctor.
Thursday, July 17, 2014
2014 WSA National Convention Questions Answered Part 1- Inheritance
During the convention, I spoke about sensory motor pathways and the genetics of WS. I plan to have a few new posts that share the information I presented at the convention in the near future. Look for those and others that have been requested (such as urinary and kidney issues in WS and sleep).
I was busy keeping notes of questions that ventured my way throughout the week. Since many questions we have are on other's minds, I thought I'd answer them in a series of blog posts. I'll post info as I learn them :)
Q1: Is the likelihood of a WS parent having a child without WS really 50%?
This question came up during the genetics session. The reason behind this is that some families are skeptical that there really is a 50% chance of their child with WS eventually having a typical offspring. We rarely hear of WS adults with children and those we do hear of often have children with WS. While I don't know of nor have actual records of parents who have Williams syndrome and have typical children, all the literature says that the likelihood is 50%.
This is because of the process of meiosis. When a person creates eggs or sperm their cells go through a process called meiosis where they duplicate their chromosomes, shuffle the genes during crossing over and then distribute them into two groups and divide. In the second half of this process, they divide again to create two unique cells. The result is four unique gametes each containing half of the parent's chromosomes.
So, if a person with WS divides their chromosomes in half, one half of them will contain the deleted portion and one half would contain the full genetic sequence. From this point, we call the 50% the probability of inheritance but in reality, it's all chance. If you flip a coin a couple of times is it likely you'll get heads both times? Yes! So it's fair to say that a person with WS could potentially have children who all have WS. Now consider the full genetic potential of one person. In her lifetime, one female creates upwards of 6 million eggs before she is born and a male can produce nearly 525 billion sperm! So if you flip a coin 6 million or 525 billion times guess what the likelihood of getting heads? 50%. That explains why you might see families with parents who have WS and their children all have WS. It's the game of statistics.
I'm unaware of studies that are following data on this topic but with the improvement of the WS registry and parents asking for this information I could see this information being available in the future.
Learn more about inheritance and the basics of genetics and WS here.
If you have never experienced a National convention for WS, I highly recommend you try for the Ohio convention in 2016. I found many outlets for financial support and made the trip affordable for my family. The wealth of information you gain and the networking you can participate in is worth every cent. In the meantime, check out www.williams-syndrome.org to find audio recordings of the convention sessions for sale.
Future blog topic requests that came my way during the convention:
Urinary and kidney issues in WS
Improve the gene list and functions
Anxiety, obsessions and meltdowns
Causes of sleep issues in WS
Teaching social skills and friendly conversation
Have any other requests or more info on this blog post? Leave a comment. I'd love to have powerful dialog occur on these posts from parents like you. Stay tuned for more Convention Questions Answered within the next few days!
See the answer to question 2: radioulnar synostosis here.