by Neil Bauman, Ph.D.
A young mother wrote:
My husband and I just found out over the past few months that our daughter is deaf, due to LVAS [large vestibular aqueduct syndrome]. She passed her newborn hearing test in her right ear and failed in her left, but a month later when we did the ABR [auditory brainstem response] she was not responding to sound at any level in either ear, which we were told is equal to being deaf. We are looking into a cochlear implant and are very hopeful. My question is, how likely is it that this will reoccur in future children? This is our first child, and I had always dreamed of having 3 or 4 children, now I am very scared.
Large Vestibular Aqueduct Syndrome (LVAS) is also known as Enlarged Vestibular Aqueduct Syndrome (EVAS).
With LVAS, doctors think that the extra-large vestibular aqueduct (really just a hole in your skull) allows the contents of the endolymphatic sac (on the inside of your skull) to flow (backwards) though the endolymphatic duct into the inner ear where it somehow causes hearing loss.
LVAS is a relatively new diagnosis, even though the underlying condition has been around for awhile, but no one knew about it until recently. Doctors just classified hearing loss from LVAS under “idiopathic hearing loss” which simply means hearing loss of unknown causes.
The good news is that I know a lot of kids with LVAS that have responded very well to cochlear implants. So I am hopeful that your daughter will have similar results if you choose to go through with it.
Don’t be scared about having more children. They are worth it whether they have hearing loss or not. You can find a lot of help and support on the LVAS list that I set up for people with LVAS. As a matter of interest, most of those on this list are mothers in just your situation. To join this special list, click here then scroll to the bottom where you can fill in your email address and subscribe to the LVAS list. While you are there read the whole article on LVAS.
Don’t put off having more children just because there is a possibility of them having LVAS. Even if all of them had LVAS and lost their hearing, you would still love them. They will be normal except for not hearing well. I knew before my children were born that one or more of them would be born hard of hearing—and my wife and I are still glad we had them—even though one has a severe hearing loss like me.
Now to answer your question as to how likely any of your future children might have LVAS. (The following works for any other recessive hearing loss syndrome as well for that matter.) Since LVAS is a recessive hereditary trait, both you and your husband must already be carriers of the recessive LVAS gene. Furthermore, both of you need to pass this recessive gene on to your child in order for your child to have LVAS.
Remember, genes come in pairs, and you only pass on one gene of each pair to each child, so there is a 50% chance you will pass on the normal gene and a 50% chance you will pass on the LVAS gene. The chances that both you are your husband will both pass on the LVAS gene at the same time is only 25.
Here are the probabilities (assuming there is only one LVAS gene—but this is not certain, there may be more, so the probabilities may be even less than shown below.
25% chance your child will have LVAS (child receives an LVAS gene from each of you).
50% chance your child will be a carrier of the recessive LVAS gene, but will NOT have LVAS (child only receives an LVAS gene from one of you).
25% chance the child will not have any LVAS genes and thus will not have LVAS, nor be a carrier of LVAS. (child does not receive a LVAS gene from either of you).
So each of your future children only has a 25% chance of actually having LVAS.
Mind you, this is how it works out on the average. However, it could be that all of your future children will have LVAS, or none of them. Think of flipping a coin. On the average you’ll get heads 50% of the time. However, it is possible to flip a coin 10 times and get 10 heads in a row (possible, but extremely unlikely). This is the way it works with having children with LVAS too.
If it were me, I’d have all the children you want. We (hard of hearing people) live happy, successful and fulfilled lives in spite of our hearing losses. There is no reason your children won’t also.