Pigment gene expression in protan color vision defects

Area of Science:

• Ophthalmology
• Genetics
• Vision Science

Background:

• Congenital color vision defects are typically inherited genetic conditions affecting color perception.
• Protan defects involve anomalies in the red cone photopigment (L-pigment).
• Understanding the genetic basis of these defects is crucial for diagnosis and potential therapies.

Purpose of the Study:

• To investigate the genetic basis of congenital protan color vision defects in male eye donors.
• To identify and characterize individuals with protanopia and protanomaly at the genetic and pigment expression level.

Main Methods:

• Screening of 150 male eye donors.
• Analysis of photopigment gene expression, specifically focusing on L and M pigment genes.
• Genotyping and characterization of identified genetic variations.

Main Results:

• Four male donors (approximately 2.7%) were identified with a lack of L pigment genes, indicating congenital protan color vision defects.
• One donor was a protanope, expressing only a single X-chromosome photopigment gene encoding an M pigment.
• Three donors were protanomalous, expressing two spectrally distinct M pigments, with the primary expressed M pigment differing in amino acid sequence from those in color-normal individuals.

Conclusions:

• The study successfully identified individuals with congenital protan color vision defects through genetic screening of eye donors.
• Genetic variations in photopigment genes, particularly the L-pigment gene, are directly linked to protan color vision defects.
• The findings provide valuable insights into the molecular mechanisms underlying protanomaly and protanopia.