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Potential Link Between Youth Hearing Loss & Genetics
Early onset hearing loss potentially caused by gene mutation can be found worldwide, study finds.
One scientist has made an important discovery which changes the way we think about early onset hearing loss. Justin Pater, a PhD researcher at Memorial University, recently published a journal where he documents his discovery that a known gene mutation has the ability to make children develop hearing loss from the age of 3 or 4.
The mutation itself is not new and has been found in other countries around the world. But the fact that it has the ability to lead to hearing loss is something we haven’t found before. Pater found the mutation in 1% of the population of Newfoundland. This hearing loss is based on the middle and higher frequencies, sounds like birds chirping, or the ‘s’ or ‘t’ sound in English. Lower frequencies are unaffected, his study finds.
Ideal conditions
A native of Montague, Prince Edward Island in Canada, Pater benefited from an ideal study group in the Newfoundlanders. The province is a ‘founder’ population; those who live there are likely to have descended from small tribes of British settlers. As a result, family trees are large and any gene mutation that somebody picks up is likely to spread quickly through the group.
Pater and his team gathered data about hearing loss in particular families around Newfoundland. As they recorded the data, they noticed that hearing loss cases within families showed very similar symptoms. This led them to believe that the hearing loss was in fact genetic. With this information, the team began trying to find a gene responsible for the hearing loss. In a process called next generation sequencing, it only took six months to isolate the mutated gene.
The science: mutation in the gene
The mutation was found in a gene known as CLDN14. This gene produces a protein which is important for keeping cell structure strong in ears. However, when the gene is mutated, the tight junctions which are essential for strong cell structures are formed incorrectly. As a result, the ability to detect higher frequencies is gradually lost by the child with the mutated gene. This is form of hearing loss is known as called sensorineural hearing loss. Sensorineural hearing loss is not caused by environmental factors, but due to the development and structure of the inner ear itself. The hearing loss becomes present at “three or four years of age,” says Pater.
An Important Find
The findings have sparked concern from audiologists and parents alike. In the US and some other countries, a child usually receives an initial hearing test hours after they are born. If the child passes this test, then it is assumed that the child will not develop any sensorineural hearing problems. As we have learned however, this particular gene mutation means that problems will not likely surface until they are in preschool, but the delay in the child displaying symptoms could have a significant effect on their development.
Ages three and four are the most important for a child’s acquisition of language, and the inability to detect some frequencies at this stage can lead to significant speech-language issues and developmental delays. The research team hopes that their findings will be useful to identify children who are at risk of developing hearing loss at a young age. Early onset hearing loss is linked to slower development of language skills which have a host of effects like stunted social skills, poor educational attainment and eventually, a reduced earning capacity when in adulthood.
It’s no surprise that in light of these findings, many audiologists recommend regular hearing checks for young children up to the age of 4 to make sure that they are not subject to this gene mutation. The first test should be given before they are 30 months old, according to the latest research. Early identification of hearing problems in children is critical because the earlier it is found, the more effective speech pathologists and audiologists can be in mitigating its effects.
With his findings, Pater hopes that they will bring about changes in pediatric hearing loss test requirements worldwide. “I am proud to be a part of a larger team that came together to discover this mutation,” says Pater. “Approximately 10 per cent of Canadian adults are affected by hearing loss and 50 per cent of these cases are caused by genetic mutations. It is these overwhelming statistics that drew me into hearing loss research. Not only can these discoveries have a big impact right here in Newfoundland and Labrador, but so, too, can they be extended to the national and international level.”
