Prevalence of the mitochondrial 1555 A>G and 1494 C>T mutations in a community-dwelling population in Japan

Abstract

Single nucleotide polymorphisms in mitochondrial DNA, such as mitochondrial 1555 A>G (m.1555 A>G) and mitochondrial 1494 C>T (m.1494 C>T), are known to be causative mutations of nonsyndromic hearing loss following exposure to aminoglycoside antibiotics. The prevalence of the m.1555 A>G and m.1494 C>T mutations has not been reported for the general population in Japan. The purpose of this study was to investigate the prevalence of m.1555 A>G and m.1494 C>T mutations in a community-dwelling population in Japan in order to prevent aminoglycoside-induced hearing loss. We recruited participants older than 20 years of age to the Iwaki Health Promotion Project in 2014, 2015, and 2016, resulting in the recruitment of 1,683 participants. For each participant, we performed a hearing test and a genetic test for the m.1555 A>G and m.1494 C>T mutations using the TaqMan genotyping method. The m.1555 A>G mutation was detected in only 1 of the 1,683 participants (0.06%). This carrier of the m.1555 A>G mutation was a 69-year-old male with bilateral, symmetric, and high-frequency hearing loss. We provided genetic counseling and distributed a drug card advising him to avoid the administration of aminoglycoside antibiotics. In contrast, the m.1494 C>T mutation was not detected in this study population.

Hearing loss: mitochondrial mutations and antibiotic use

Researchers in Japan have measured the prevalence of two hearing loss mutations associated with antibiotic use in the general population. Two mutations in mitochondrial DNA are known to cause hearing loss upon exposure to aminoglycoside antibiotics such as gentamicin. One mutation is found in 3% of Japanese hearing-impaired outpatients, but the frequency in the general population is unknown. A team led by Akira Sasaki of Hirosaki University carried out genetic and hearing tests in 1,683 community-dwelling subjects. They found one person who had one of the mutations. Although this subject had no known history of aminoglycoside antibiotic injection, he exhibited hearing loss at high frequencies. He was provided with genetic counseling and a drug use warning card. The second mutation was not found in the study population.