My Family’s Genetic Puzzle: Solved
For many years, my family was unique when it came to stories about hearing loss. Everyone in my family, for five generations, was born with hearing in the normal range. My mom started losing her hearing as a teen and became deaf at the age of 27. “I was at a family BBQ and all of a sudden, I realized I couldn’t hear anything,” Mom shared. “I could see that lips were moving, but no sound was coming out.” Just like that, my Mom became deaf. Her five siblings were also deaf or hard of hearing.
I am the youngest of five siblings. My sister Linda was almost three years old when she fell off of a chair and hit her head on the corner of a baseboard. Later that week, my Mom noticed that she wasn’t responding to people. She stopped talking over time. She was diagnosed with a profound hearing loss. My brother Dennis grew up with normal hearing. At the age of 36, a wooden beam hit him on the head in a work related accident, and he woke up in the hospital with a severe hearing loss. My sister Jeanie grew up with a unilateral hearing loss and started to lose more hearing near the same age my mom had. In her mid-forties, Jeanie slipped on a rug and became profoundly deaf. My brother Kenny developed a moderate hearing loss in his 40’s.
My own story began when I became very sick with a high fever as a child. My parents believed it was that illness while I was in elementary school which triggered my hearing loss. My first hearing aid was given to me when I was nine-- but I only wore it when at school. I found that the hearing aid caused headaches and tinnitus and I often took it off after school. I didn’t touch it during the summer. When I was 19, I was waterskiing on my bare feet at a high speed and fell sideways into the water. For weeks afterwards, I thought I just couldn’t get the water out of my ear. I had become profoundly deaf. From that point on, hearing aids were a constant thing in my life. Years later, my brother Kenny also lost some hearing from “barefooting”.
Whenever I would share my family’s story about how we all became deaf or hard of hearing, people would be incredulous at the events that led to hearing loss. “Y’all need to stop banging your heads,” one person remarked.
I knew that genetics obviously played a part, as there were so many family members sporting hearing aids. We went through the testing at Gallaudet for the Connexin gene and it came back negative.
My friend, Tina Childress, an audiologist, said to me one day, “I think your family has Large Vestibular Aqueduct Syndrome (LVAS).”
So off I went to the ENT for a pretty picture of the inside of my head. “No, you don’t have LVAS,” said the radiologist who read the scan.
I then sent the CT scan results to Anne Madeo, a genetic researcher at the National Institute on Deafness and other Communication Disorders, part of the National Institutes of Health, to examine. Anne asked some questions about our family history to construct a “pedigree”, a term that researchers use to describe a family in graph form.
“Because the inheritance of hearing loss appeared to come from mothers to all of their children, but no incidence of hearing loss occurring from fathers to their children, we thought there was a very good chance that it was due to a mutation in one of the mitochondrial genes,” said Anne.
With our permission, Anne assembled a team (Andrew Griffith, Penny Friedman, and Thomas Friedman) from NIH and we all gathered at my home. The team spent the day collecting information from each family member and drew blood for genetic testing.
We learned that we are the third family in the world identified with a mutation in the mitochondrial gene. The specific mutation is called 7510T>C. The most interesting thing to family members was learning that our specific mutation, like all mitochondrial genes, is passed through female family members. There is nearly a 100% guarantee of passing the mutation from a female to the offspring, but not from the males.
What this means for my children is that my daughter will have children with this gene, but my sons will not.
People have asked me why we pursued the genetic testing in our family. There were two reasons for it. One of my nieces is hard of hearing. My other niece began to suspect that she might be losing her hearing. However, tests showed that her hearing was within normal limits. A nephew also had an episode where he thought he was losing his hearing as well. So we wanted to figure out the genetic pattern and see how the gene moved through the family. The other reason was simple: after years of questions from other people, we wanted to see if we had a name for the gene.
The results were surprising for my nieces and nephews. The niece who thought she had the gene was relieved to find out she didn’t. While she was happy to find out that she didn’t have the gene, she also felt a sense of “survivor guilt” in knowing this information. My other niece has it and will pass it on to her children should she have kids. My nephews didn’t participate in the research, but from what we know about the gene, we know the conclusion for each of them. One nephew has the gene, the others do not. The biggest shock came to me months later, when a cousin of mine obtained hearing aids and then mentioned that her kids were struggling in the classroom. I suddenly realized that the gene was in their family as well. Her grandmother and my mother were sisters.
“I think sometimes, on a really fundamental level, it can make you wonder who you are when you learn something like this about a specific gene mutation,” said Anne. “Even though I know and try to tell people that we all carry gene mutations--they don’t define us. Yet, suddenly you’ve learned something fundamental about yourself that you didn’t know before.”
Sometimes learning about genetic results can shake up a family or cause individuals to blame one another. “That probably happens most in families that weren’t doing well already,” explained Anne. “Maybe it wasn’t a strong marriage, maybe the diagnosis in the family was really tough, maybe they’re going through an already stressful time. Not every family (at all) starts pointing fingers.”
For my own family, the information we learned was simply an interesting piece of the puzzle that has been unfolding over the years. My only beef with the researchers is that they didn’t give this gene a cool name. So in my family, we’re naming this gene in honor of my mother and grandmother: the Valle gene.
For more information on genetic research