Maternally inherited non-syndromic hearing loss is linked with a novel mitochondrial ND6 gene mutation

Background: Maternally inherited non-syndromic hearing loss is linked with mitochondrial DNA mutations.

Aim: This investigation demonstrates the features of a Chinese pedigree suffering from maternally inherited non-syndromic hearing loss.

Methods: Biochemical characterizations included the measurements ofprotein synthesis levels, membrane potential, and the synthesis of reactive oxygen species (ROS) and adenosine triphosphate (ATP) using cybrid cell lines derived from an affected matrilineal subject and control subject.

Results: Non-congenital early or late-onset/development hearing impairment has been observed in 4 of 9 in a family (matrilineal), with different degrees of hearing impairment, ranging from normal to severe. A pedigree's whole mitochondrial genome sequence analysis revealed the homoplasmic m.14502 T > C (I58V) mutation at ND6's isoleucine location-58, and specific mitocchondrial DNA polymorphisms set haplogroups M10 were highly conserved. In vitro models indicated that m.14502 T > C mutation-derived respiratory deficiency decreases ND6 protein synthesis, mitochondrial membrane potential, and ATP synthesis. These mitochondrial dysregulations enhance the generation of ROS in the mutant cells. Identifying nuclear modifiers is essential for elucidating hearing loss's pathogenesis and furnishing novel therapeutic interventions.

Conclusions: The m.14502 T > C mutation should be considered an inherited risk factor that can help diagnose. The data of this investigation help counsel families of individuals with hearing loss.