Genes and Auditory Processing
Auditory processing is a skill heavily influenced by genes, according to a study at the National Institute on Deafness and Other Communication Disorders (NIDCD).
The finding, published in the August 2007 issue of Human Genetics, may help researchers better understand auditory processing disorders (APDs).
To determine the genetic influence on auditory processing skills, NIDCD researchers studied identical and fraternal twins attending annual national twins festivals in Twinsburg, Ohio, from 2002 through 2005. A total of 194 same-sex sets of twins participated in the study—138 identical pairs and 56 fraternal pairs, ages 12-50.
The twin sets took five tests frequently used to identify auditory processing difficulties in children and adults. In all but the filtered-words test, researchers found a significantly higher correlation among identical twins than among fraternal twins, indicating that differences in performance had a strong genetic component. Participants showed the widest ability range on dichotic listening tests; as much as 73% of the variation in dichotic listening ability was due to genetic differences, a magnitude comparable to well-known inherited traits such as height. Conversely, the ability to understand filtered words showed a high correlation among all twins, indicating that variation in the skill is primarily due to environmental influence.
The finding that normal twins show such wide variation in their dichotic listening abilities, and that the differences are mostly due to genetic variation, adds a new perspective to the understanding of auditory processing disorders. View the press release or the abstract.
Otosclerosis Gene Identified
Belgian researchers identified a gene linked to otosclerosis that they hope will lead to new treatments for the common cause of hearing loss that affects approximately one in 250 people.
The Antwerp team focused on a gene called TGBF1, which was already known to play a role during the embryonic development of the ear and to be active in the otosclerotic bone, according to a study announced at the European Society of Human Genetics conference.
Using a technique called single nucleotide polymorphism (SNP) analysis to search for tiny variations in genetic makeup, researchers found that patients from Belgium and the Netherlands with otosclerosis often had a specific variant in the TGBF1 gene. Similar results were found in a second analysis of French patients.
"Combining the data from both groups gave a very significant result, from which we were able to conclude that we were the first to identify a gene that influences the susceptibility for otosclerosis," said lead researcher Melissa Thys from the University of Antwerp. "And we were also able to show that a more active variant of this gene is protective against the disease." Visit the European Journal of Human Genetics for an abstract.