Objective Two genetic variants in the lipoprotein cholesterol pathway, hepatic lipase (LIPC) and ATP-binding aassette sub-family A member 1 (ABCA1), were discovered to be associated to intermediate and large drusen, as well as advanced AMD in recent studies. In this study, we evaluated whether these variants is associated with serum lipids, and whether these variants and serum lipids are independently associated with early AMD in a Chinese population.
Methods  Case-Control study. Patients of early AMD and normal control subjects were recruited through a community-based eye disease–screening program in urban Beijing. Five novel genes involved in the lipoprotein cholesterol pathway, LIPC, ABCA1, APOE, RORA and LPL genes, as well as the CFH and ARMS2/HTRA1 genes/regions, were genotyped. Genotyping for SNPs were performed using methods of PCR followed by allele-specific restriction enzyme digestion or Sequenom MassARRAY technology. Serum levels of total cholesterol, low-density lipoprotein (LDL), HDL, and triglycerides were determined. Logistic and linear regressions were used to evaluate associations between serum lipids, LIPC /ABCA1genotypes and AMD.
Results A total of 366 subjects were enrolled in the study, including 172 controls and 194 cases with early AMD. Controlling for age, gender, education, smoking, body mass index, and history of hypertension and hyperlipidemia, the number of minor alleles (A) of the HTRA1 gene was significantly associated with an increased risk of early AMD (P=0.018).  None of the genetic variants in lipoprotein cholesterol pathway were associated with early AMD (P＞0.26). Mean level of triglycerides was lower (P=0.008) in cases of early AMD compared with controls. However, in models controlling for environmental and genetic covariates, the association was not detected (P=0.16). The T allele of LIPC gene was associated with higher levels of HDL (P=0.031 for trend). The mean level of HDL was 1.37mmol/L (±0.31mmol/L) for the CC genotype and 1.79mmol/L (±0.27mmol/L) for the TT genotype. Association between ABCA1 genotype and serum lipids was not detected in this study.
Conclusion Serum lipid biomarkers and genetic variants in lipoprotein cholesterol pathway, such as LIPC and ABCA1 genes, were not associated with early AMD in this Chinese Population.