Testing for Connexin 26:
One Family's Story
We had never heard of Connexin 26 ... but boy, has it changed our lives! My husband and I have three children. Kurt is 6, Abby is 4, and Ryan is 9 months old. We began to have suspicions about Kurt's hearing around 3 months old, but denial played a part until he was 9 months old. We then had his hearing tested and found out he had a severe to profound loss in both ears. In 2002, a letter was sent home from Kurt's school addressed to us from Gallaudet University asking if we wanted to be a part of a genetic study. We were not sure at first, but then thought...what the heck? It was free and maybe we would find out some answers to our questions. In one way, the answers were not very important because the outcome would not change. But in another way, the answers were important because, as parents, we were finding many reasons to think something we had done had caused Kurt's deafness.
We decided to go ahead and have blood samples tested for Kurt, my husband, and me for connexin 26. About 8 months later I received a call from a genetic counselor at Gallaudet University stating that they found the cause of Kurt's deafness. My heart immediately began beating about 3 times the speed it normally does. The counselor stated that both of Kurt's connexin 26 genes are changed, causing a hearing loss. She then informed me that it is a recessive gene and they did find that my husband Tom and I both have 1 changed connexin 26 gene and one unchanged connexin 26 gene. Because one is unchanged, we are hearing. With each child we have together, we have a 25% chance of having a child with a hearing loss because we each pass one of our connexin 26 genes down to our child. We each have a 50% chance of passing down our changed gene versus our unchanged gene. If the child receives a changed gene from both of us, the child will have a hearing loss.
I immediately began crying when I got off of the phone. Not because I was sad or mad, but because I had an answer. Kurt is the first Deaf child in both our families. Crazy thoughts were going through both of our heads as to why he was Deaf. Did I listen to music that was too loud during a crucial time of development when I was pregnant? Did I hold my breath under water too long when I was swimming? Tom was in Desert Storm...did that have something to do with it? These questions may sound crazy, but they were always in the back of our minds. This gave us some much needed relief. Relief we didn't know we needed until after we found out his deafness was genetic.
The study of connexin 26 genes began in 1997. The study is still so new that information found from the research is changing all the time. Geneticists used to think that someone with two changed genes would have a severe to profound loss. They have now found that a person with two changed connexin 26 genes can be hard of hearing. The studies are also showing that if a person is born hearing, and has two changed genes, they will lose their hearing in the first months of life.
Abby was born hearing. At 7 weeks old she had an ABR that showed normal hearing results. (Because Kurt was born Deaf, and we did not know it was genetic at the time Abby was born, we had no reason to think she would lose her hearing.) The only hearing test she had after her 7 week old ABR was a preschool hearing test that she passed at age 3. This was also before we found out Kurt's deafness was genetic. Time went on, and a couple of months before Ryan was born we were informed about connexin 26. After Ryan was born, we were discussing connexin 26 with Kurt's ENT, and it made sense to all of us to have Ryan tested to see if he had any changes in his connexin 26 genes rather than testing his hearing every 6 months to see if there was any loss. At this time, we believed Abby to be hearing and there would be no possible way for her to have two changed connexin 26 genes. We decided to also have her blood tested just to see if she carried the changed genes just like Tom and I do. So Abby and Ryan were both genetically tested and about a month later the results were in. Ryan is a carrier like Tom and I with only one connexin 26 gene changed. Abby, on the other hand, has two changed connexin 26 genes. What??? She is hearing...or is she?
We had Abby's hearing tested and she has a mild to moderate loss. Her speech is age appropriate, she has been doing very well in preschool, and we noticed no signs of her having a hearing loss. She is now wearing hearing aids and loves them. How long would this have gone unnoticed if we did not have her genetically tested for changes in her connexin 26 genes? I now look back at how lucky we are to have been asked to be a part of the Gallaudet study, and how happy I am we took part in it.
Someone may ask, "Why do you need to know why your child is Deaf.the outcome is the same?" I think that person is absolutely correct. My husband and I love our children and have learned as much about deafness and Deaf culture as we can and are still learning. We believe our kids are who they are partly because of their hearing loss, and we would not want to change that. But I also think I have answered the question of "why find out" for other reasons. We would probably still think Abby was hearing today. We do not know when she lost her hearing. Was it in the first months of life and her 3-year-old preschool hearing test was wrong, or did she start losing it after her 3-year-old hearing test? If the latter is true, the study of connexin 26 genes is uncovering new information as this article goes to print.