Korean J Otolaryngol-Head Neck Surg.  2004 Mar;47(3):206-211.

The Frequency of Mitochondrial Gene Point Mutations in Korean Non-syndromic Sensorineural Hearing Loss

• Jeong HS
• Lim MJ
• Chang SO
• Kim CS
• Oh SH

Abstract

BACKGROUND AND OBJECTIVES
Mitochondrial point mutations have been shown to be responsible for syndromic and non-syndromic hearing impairment. Among these mitochondrial point mutations, 1555 A-->G, 3243 A-->G, and 7445 A-->G mutations are detected more frequently in sensorineural hearing loss (SNHL). In the present study, we evaluated the frequency of these three mitochondrial mutations among the non-syndromic SNHL population in Korea. SUBJECTS AND METHOD: To determine the frequency of three mitochondrial point mutation 1555 A-->G, 3243 A-->G, and 7445 A-->G, we examined 129 unrelated SNHL outpatients using restriction fragment length polymorphism. And to confirm these point mutations, we analyzed mitochondrial DNA with point mutations by direct sequence analysis. RESULTS: The frequency of mitochondrial gene mutation in the unrelated sensorineural hearing impaired patients in the Korean population was 1555 A-->G: 2.3% (3/129), 3243 A-->G: 0.7% (1/129), 7445 A-->G: 0% (0/129). CONCLUSION: These results regarding Koreans are similar to those of Japanese. Each member in a family with 1555 A-->G mitochondrial point mutation had variable hearing levels (different phenotype) in spite of the same mitochondrial point mutation. The pathogenesis of these mitochondrial point mutations in hearing should be further investigated and a study should be performed using large number of families and functional experiments to elucidate the meaning of these point mutations.

Keyword

Sensorineural hearing loss; Mitochondria; Point mutation

MeSH Terms

Asian Continental Ancestry Group
DNA, Mitochondrial
Genes, Mitochondrial*
Hearing
Hearing Loss
Hearing Loss, Sensorineural*
Humans
Korea
Mitochondria
Outpatients
Point Mutation*
Polymorphism, Restriction Fragment Length
Sequence Analysis
DNA, Mitochondrial