Led by Xue Zhong Liu, M.D., Ph.D., associate professor and Director of Research in the Department of Otolaryngology, the study found that testing for some of the most common mutations that cause sensorineural hearing loss in a targeted way, rather than through generalized screening of hearing loss patients, yields the best results.
“Our study supports the considerable value of genetic testing in establishing an etiology for childhood hearing loss,” Liu said. “Given its high yield, mutation screening should be considered an early step in the diagnostic evaluation of pediatric hearing loss. However, its role in adults seems considerably more limited and is yet to be defined.”
More than 28 million Americans of all ages are affected by hearing loss, and genetic changes underlie the majority of cases.
For their study, “Etiologic Diagnosis of Nonsyndromic Genetic Hearing Loss in Adult vs. Pediatric Populations,” Liu and his team screened 384 patients between the ages of 3 months and 80 years with nonsyndromic sensorineural hearing loss who visited the University of Miami Ear Institute between 2001 and 2010. Their blood was screened for deafness genes and they underwent audiometric testing. Their patient and family histories also were taken.
Mutations in the most common recessive deafness genes, GJB2 and GJB6, were identified in 23 of the 163 pediatric patients (14 percent), but only 3 of 221 adults (1 percent). Thirteen percent of the pediatric patients also were determined to be carriers of a single mutation.
Mitochondrial testing in adults returned a higher rate (3 percent) than the 1 percent usually reported. Identifying this mutation early, the researchers said, will provide carriers with a number of options, including risk factor avoidance and pharmaceutical options to prevent hearing loss from progressing or improving.
In addition to Liu, the other Miller School co-authors were lead author Peter J. King, M.D., chief otolaryngology resident; Xiaomei Ouyang, M.D., research associate in pathology; Lilin Du, research associate; Denise Yan, Ph.D., research assistant professor; and Simon I. Angeli, M.D., professor of otolaryngology.
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