Mitochondrial sequence changes in keratoconus patients

Area of Science:

• Genetics
• Ophthalmology
• Mitochondrial Biology

Background:

• Keratoconus (KTCN) is a progressive corneal disease of unknown etiology.
• Mitochondrial dysfunction has been implicated in various human diseases.
• The role of mitochondrial DNA (mtDNA) mutations in KTCN pathogenesis remains largely unexplored.

Purpose of the Study:

• To investigate the presence of mutations in the mitochondrial genome of Saudi patients diagnosed with keratoconus (KTCN).
• To determine if specific mtDNA mutations are associated with KTCN development or progression.

Main Methods:

• Full mitochondrial genome sequencing was performed on 26 Saudi patients with KTCN.
• Sequencing data was compared against 100 ethnically matched control individuals without KTCN.
• Analysis focused on identifying nonsynonymous and synonymous sequence variations.

Main Results:

• Potentially pathogenic nonsynonymous mtDNA mutations were identified in 10 (38.5%) KTCN patients.
• Mutations were found in Complex I, tRNA(Glutamine), tRNA(Tryptophan), tRNA(Asparagine), tRNA(Histidine), and tRNA(Leucine2).
• These mutations were absent in controls, with 4 novel and 5 previously reported variations; 9 were homoplasmic.

Conclusions:

• Mitochondrial DNA mutations may represent a genetic risk factor contributing to keratoconus.
• The proposed mechanism involves oxidative stress, indirectly influencing KTCN development and progression.
• Confirmation in larger, multi-ethnic cohorts is necessary to validate these findings.