Abstract
Purpose :
The study aimed to investigate the genetic basis of 30 unrelated Leber's hereditary optic neuropathy (LHON) patients from south India. To explore the involvement of nuclear genomic alterations in the primary mutations negative cases in order to understand LHON pathogenesis.
Methods :
Genomic DNA was extracted from peripheral blood samples collected from all study participants, and underwent whole mitochondrial DNA sequencing and whole exome sequencing. The whole mitochondrial genome (16.5 kb) was amplified with twenty four different primer sets and subsequently characterized through Sanger sequencing. Whole exome Sequencing (WES) was performed using Agilent sure select XT Human All Exon V5 kit. Eventually, the functional contributions of nuclear genes implicated in electron transport chain (ETC) assembly, specifically NDUFV1, NDUFS7, and NDUFA3 were evaluated through targeted genetic knockout experiments on the 661W RGC’s cell line.
Results :
Whole mtDNA sequencing revealed primary mtDNA mutations in 30 % of the probands (n=9), secondary mtDNA mutations in 40 % of the probands (n=12) and no mitochondrial changes in 30 % of individuals (n=9). Furthermore, WES analysis determined pathogenic mutations in 11 different nuclear genes, especially in cases with secondary mtDNA mutations (n=6) or no mtDNA mutations (n=6). Consistently, genetic knock out of the NDUFV1, NDUFS7 and NDUFA3 in 661W mouse RGC cell line showed decreased ATP production and decreased membrane potential.
Conclusions :
This is the first study from our ethnic group provide valuable insight into LHON genetic predisposition, particularly in cases lacking primary mtDNA mutations. In addition, the functional assessment of the candidate genes provides substantive evidence supporting its relevance to LHON.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.