Feasibility of a bilateral 4000-6000 Hz notch as a phenotype for genetic association analysis.
OBJECTIVE
Noise-induced hearing loss (NIHL) is a worldwide health problem and a growing concern among young people. Although some people appear to be more susceptible to NIHL, genetic association studies lack a specific phenotype. We tested the feasibility of a bilateral 4000-6000 Hz audiometric notch as a phenotype for identifying genetic contributions to hearing loss in young adults.


METHODS
A case-control-control study was conducted to examine selected SNPs in 52 genes previously associated with hearing loss and/or expressed in the cochlea. A notch was defined as a minimum of a 15-dB drop at 4000-6000 Hz from the previous best threshold with a 5-dB 'recovery' at 8000 Hz.


METHODS
Participants were 252 individuals of European descent taken from a population of 640 young adults who are students of classical music. Participants were grouped as No-notch (NN), Unilateral Notch (UN), or Bilateral Notch (BN).


RESULTS
The strongest evidence of a genetic association with the 4000-6000 Hz notch was a nonsynonymous SNP variant in the ESRR- gene (rs61742642:C> T, P386S). Carriers of the minor allele accounted for 26% of all bilateral losses.


CONCLUSIONS
This study indicates that the 4000-6000 Hz bilateral notch is a feasible phenotype for identifying genetic susceptibility to hearing loss.
a * Communication Sciences & Disorders, University of North Carolina at Greensboro , USA.
Susan L
SL
Phillips
b Math & Statistics, University of North Carolina at Greensboro , USA.
Scott J
SJ
Richter
c Music Research Institute, University of North Carolina at Greensboro , USA.
Sandra L
SL
Teglas
d Communication Sciences & Disorders, Northern Arizona University , Flagstaff , USA.
Ishan S
IS
Bhatt
e Communication Sciences & Disorders, Appalachian State University , Boone USA.
Robin C
RC
Morehouse
f Epidemiology, Duke University , Durham , United States.
Elizabeth R
ER
Hauser
g Center for Biotechnology, Genomics & Health Research, University of North Carolina at Greensboro , USA.
Vincent C
VC
Henrich
D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D001299:Audiometry / Q000379:methods*; D001309:Auditory Threshold; D016022:Case-Control Studies; D005240:Feasibility Studies; D005260:Female; D005787:Gene Frequency; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D006309:Hearing / Q000235:genetics*; D006317:Hearing Loss, Noise-Induced / Q000175:diagnosis* / Q000235:genetics* / Q000503:physiopathology; D006801:Humans; D008297:Male; D009622:Noise / Q000009:adverse effects*; D010641:Phenotype; D010865:Pilot Projects; D020641:Polymorphism, Single Nucleotide; D011237:Predictive Value of Tests; D012307:Risk Factors; D055815:Young Adult
Hearing conservation; medical audiology; noise; syndromes/genetics