Mitochondrial DNA analysis in primary congenital glaucoma

Area of Science:

• Ophthalmology
• Genetics
• Cell Biology

Background:

• Primary congenital glaucoma (PCG) is a severe form of glaucoma with complex etiology.
• Mitochondrial dysfunction and oxidative stress are implicated in various forms of glaucoma.
• Mitochondrial DNA (mtDNA) plays a crucial role in cellular energy production and is susceptible to damage.

Purpose of the Study:

• To screen the mitochondrial genome for nucleotide variations in patients with primary congenital glaucoma (PCG).
• To investigate the association between identified mtDNA variations and potential pathogenic mechanisms in PCG.

Main Methods:

• Full mitochondrial genome sequencing (excluding the D-loop) was performed on 35 PCG patients and 40 controls.
• Polymerase chain reaction (PCR) was used to amplify the entire coding region of the mitochondrial genome.
• Sequences were analyzed against the human mitochondrial reference sequence NC_012920.

Main Results:

• A total of 132 nucleotide variations were identified in PCG patients, compared to 58 in controls.
• 44 novel mtDNA variations were discovered, with 31.81% being non-synonymous and 62.12% synonymous.
• Twenty PCG patients (57.14%) exhibited mtDNA sequence changes associated with elevated reactive oxygen species (ROS) production, potentially leading to oxidative stress (OS).

Conclusions:

• Non-synonymous mtDNA variations may impair the respiratory chain and oxidative phosphorylation (OXPHOS), leading to reduced ATP production and increased ROS.
• This mitochondrial dysfunction and subsequent OS can negatively impact trabecular meshwork (TM) development and retinal ganglion cell (RGC) survival, contributing to PCG.
• Early diagnosis of mtDNA variations and prompt antioxidant therapy could mitigate OS-induced damage, potentially improving visual outcomes in PCG patients.