» Articles » PMID: 35071519

Novel M.4268T>C Mutation in the Mitochondrial TRNA Gene is Associated with Hearing Loss in Two Chinese Families

Overview
Specialty General Medicine
Date 2022 Jan 24
PMID 35071519
Authors
Affiliations
Soon will be listed here.
Abstract

Background: Herein, we report the genetic, clinical, molecular and biochemical features of two Han Chinese pedigrees with suggested maternally transmitted non-syndromic hearing loss.

Aim: To investigate the pathophysiology of hearing loss associated with mitochondrial tRNA mutations.

Methods: Sixteen subjects from two Chinese families with hearing loss underwent clinical, genetic, molecular, and biochemical evaluations. Biochemical characterizations included the measurements of tRNA levels using lymphoblastoid cell lines derived from five affected matrilineal relatives of these families and three control subjects.

Results: Three of the 16 matrilineal relatives in these families exhibited a variable seriousness and age-at-onset (8 years) of deafness. Analysis of mtDNA mutation identified the novel homoplasmic tRNA 4268T>C mutation in two families both belonging to haplogroup D4j. The 4268T>C mutation is located in a highly conserved base pairing (6U-67A) of tRNA. The elimination of 6U-67A base-pairing may change the tRNA metabolism. Functional mutation was supported by an approximately 64.6% reduction in the level of tRNA observed in the lymphoblastoid cell lines with the 4268T>C mutation, in contrast to the wild-type cell lines. The reduced level of tRNA was below the proposed threshold for normal respiration in lymphoblastoid cells. However, genotyping analysis did not detect any mutations in the prominent deafness-causing gene GJB2 in any members of the family.

Conclusion: These data show that the novel tRNA 4268T>C mutation was involved in maternally transmitted deafness. However, epigenetic, other genetic, or environmental factors may be attributed to the phenotypic variability. These findings will be useful for understanding families with maternally inherited deafness.

References
1.
Zhang S, Zhang Y, Dong Y, Guo L, Zhang Z, Shao B . Knockdown of Foxg1 in supporting cells increases the trans-differentiation of supporting cells into hair cells in the neonatal mouse cochlea. Cell Mol Life Sci. 2019; 77(7):1401-1419. PMC: 7113235. DOI: 10.1007/s00018-019-03291-2. View

2.
Yao J, Lu Y, Wei Q, Cao X, Xing G . A systematic review and meta-analysis of 235delC mutation of GJB2 gene. J Transl Med. 2012; 10:136. PMC: 3443034. DOI: 10.1186/1479-5876-10-136. View

3.
Zhang M, Han Y, Zhang F, Bai X, Wang H . Mutation spectrum and hotspots of the common deafness genes in 314 patients with nonsyndromic hearing loss in Heze area, China. Acta Otolaryngol. 2019; 139(7):612-617. DOI: 10.1080/00016489.2019.1609699. View

4.
Yu X, Liu W, Fan Z, Qian F, Zhang D, Han Y . c-Myb knockdown increases the neomycin-induced damage to hair-cell-like HEI-OC1 cells in vitro. Sci Rep. 2017; 7:41094. PMC: 5253735. DOI: 10.1038/srep41094. View

5.
Wang J, Zhao N, Mao X, Meng F, Huang K, Dong G . Obesity associated with a novel mitochondrial tRNACys 5802A>G mutation in a Chinese family. Biosci Rep. 2019; 40(1). PMC: 6944677. DOI: 10.1042/BSR20192153. View