Abstract
Purpose: :
A genetic variant in the high density lipoprotein (HDL) cholesterol pathway, hepatic lipase (LIPC), was discovered to be associated with age-related macular degeneration (AMD) in our genome-wide association study1. We evaluated whether LIPC is associated with serum lipids and determined if the gene and serum lipids are independently associated with AMD.
Methods: :
DNA and serum samples from 318 advanced AMD cases with geographic atrophy (n = 123) and neovascular disease (n=195) and 140 controls were evaluated. AMD status was based on ocular examination and fundus photography. Genotypes were determined for 8 variants associated with AMD: two CFH variants, C2, CFB, C3, CFI, the LOC387715/HTRA1 gene region, and LIPC. Fasting blood specimens were obtained at baseline, and serum levels of total cholesterol, low density lipoprotein (LDL), HDL, and triglycerides were determined. Logistic regression was used to evaluate associations between serum lipids, LIPC genotype and AMD. The relationship between LIPC and serum lipids was determined using logistic and linear regression.
Results: :
The minor T allele of the LIPC gene was associated with a reduced risk of AMD (Odds Ratio (OR) = 0.4, 95% Confidence Interval (CI) (0.2 - 0.9) p (trend) = 0.01, controlling for age and sex. Mean level of HDL was lower (p =0.02), and mean level of LDL (p=0.01) was higher in cases of advanced AMD compared with controls. Higher total cholesterol and LDL was associated with increased risk of AMD with a p (trend) of 0.01 for both, in models controlling for environmental and genetic covariates.
Conclusions: :
The HDL raising allele of the LIPC gene was associated with reduced risk of AMD. Higher total cholesterol and LDL were associated with increased risk, while higher HDL tended to reduce risk of AMD. The specific mechanisms underlying the association between AMD and LIPC require further investigation.1 Fagerness JA et al. "A Genome-Wide Scan of Advanced Age-Related Macular Degeneration Suggests a Role of Genetic Loci in the Lipid Pathway". Presented at American Society of Human Genetics, 2009.
Keywords: age-related macular degeneration • genetics • lipids