Twins' Macular Pigment Optical Density Assessment and Relation with SCARB1 Gene Polymorphism

Area of Science:

• Ophthalmology
• Genetics
• Twin Studies

Background:

• Macular pigment optical density (MPOD) is crucial for retinal health.
• Genetic and environmental factors influence MPOD, but their relative contributions require further investigation.
• Twin studies provide a powerful tool to disentangle heritability and environmental influences on complex traits like MPOD.

Purpose of the Study:

• To assess the influence of genetic and environmental factors on MPOD using twin studies.
• To evaluate the association between SCARB1 gene variants (rs11057841) and MPOD levels.
• To determine the heritability of MPOD in a Lithuanian population.

Main Methods:

• A cohort of 108 healthy twins (56 monozygotic, 52 dizygotic) was recruited.
• MPOD was measured using fundus reflectance (Visucam 500) at 460 nm.
• SCARB1 rs11057841 single nucleotide polymorphisms were genotyped using real-time polymerase chain reaction.

Main Results:

• Significant positive correlation of MPOD in monozygotic twin pairs (r=0.830-0.860, p<0.0001) and negative correlation in dizygotic pairs (r=0.314-0.408, p<0.05).
• Individuals with the SCARB1 rs11057841 CT genotype (carrying a risk allele) exhibited significantly lower mean MPOD values in both eyes compared to the CC genotype.
• Heritability of MPOD was estimated to be 86% in the studied population.

Conclusions:

• Retinal pigment optical density (MPOD) is highly heritable, with an estimated 86% heritability.
• The SCARB1 rs11057841 gene variant (CT genotype) is associated with reduced MPOD, suggesting a genetic influence on macular pigment levels.
• These findings highlight the interplay between genetic predisposition and MPOD, potentially impacting age-related macular degeneration risk.