Electrical responses from human retinal cone pathways associate with a common genetic polymorphism implicated in...

Area of Science:

• Ophthalmology
• Genetics
• Neuroscience

Background:

• Myopia is the most common visual impairment, often resulting from an excessively long eye.
• Genetic factors contribute to myopia risk, but the underlying mechanisms remain unclear.
• The GJD2 gene (connexin-36) is genetically linked to myopia, forming retinal gap junctions.

Purpose of the Study:

• To investigate the association between a myopia-associated genetic locus near GJD2 and retinal function.
• To explore the role of connexin-36 in light-evoked retinal neuronal responses.
• To determine if specific retinal pathways are implicated in myopia development.

Main Methods:

• Analyzed electroretinogram (ERG) responses from 186 adult twin volunteers genotyped at the GJD2 locus.
• Utilized standard and experimental ERG protocols to differentiate rod- and cone-driven responses.
• Employed mixed linear models to assess associations between allelic dosage and ERG parameters, adjusting for covariates.
• Examined single-cell transcriptome data for GJD2 expression patterns in retinal cells.

Main Results:

• Significant associations were found between the GJD2 locus and parameters of light-adapted ERG responses, but not dark-adapted responses.
• Associations were specifically linked to cone-driven a-wave amplitudes, not rod-driven ones.
• Transcriptome analysis indicated strongest GJD2 expression in cone photoreceptors and OFF-bipolar cells.

Conclusions:

• Altered signaling in cone-driven OFF pathways may play a role in myopia development.
• The findings suggest a functional link between GJD2, retinal gap junctions, and visual signaling relevant to myopia.
• This research provides insights into the cellular mechanisms contributing to myopia.