C677T methylene-H4-folate-reductase variant decreases binocular accommodation

Area of Science:

• Ophthalmology
• Genetics
• Neuroscience

Background:

• The C677T polymorphism in the methylene tetrahydrofolate reductase (MTHFR) gene affects enzyme activity.
• This polymorphism is associated with altered levels of homocysteine, folate, methionine, and S-adenosylmethionine.

Purpose of the Study:

• To investigate the association between the MTHFR C677T polymorphism and accommodative amplitude (AA) in 100 healthy adults.
• To determine if the T allele genotype correlates with changes in visual accommodation.

Main Methods:

• Accommodative amplitude was measured using the subjective
• push-up
• technique.
• MTHFR C677T genotyping was performed on DNA from buccal cells using PCR-RFLP.
• Statistical analyses included descriptive statistics, t-tests/ANOVA for monocular vs. binocular AA, and regression models for genotype-phenotype associations.

Main Results:

• The C677T polymorphism was significantly associated with decreased binocular accommodative amplitude (p = 0.0087).
• No significant association was found between the MTHFR genotype and monocular accommodative amplitude.

Conclusions:

• The MTHFR C677T polymorphism may negatively impact the neural mechanisms of binocular vergence accommodation.
• Reduced 5-methyl-tetrahydro-folic acid and defective methionine/SAM synthesis are potential contributors to this effect.
• The findings suggest a role for methylation in vergence accommodation, potentially explaining similar issues in conditions like Down's syndrome.