High-density genotyping and functional SNP localization in the CETP gene

Area of Science:

• Genetics
• Molecular Biology
• Cardiovascular Research

Background:

• Cholesteryl ester transfer protein gene (CETP) genetic analyses often focus on limited polymorphisms within single ethnic groups.
• The regulatory regions of CETP influencing gene expression are not fully understood.

Purpose of the Study:

• To investigate natural variations in CETP and their impact on high-density lipoprotein-cholesterol (HDL-C) levels.
• To define the extent of regulatory DNA influencing CETP expression through dense genotyping.

Main Methods:

• Dense genotyping of CETP and flanking regions (15 kb upstream and downstream) in over 2,000 individuals.
• Analysis of linkage disequilibrium (LD) patterns and association of single nucleotide polymorphisms (SNPs) with HDL-C levels.
• Comparison of SNP associations across different ethnic groups to identify functional variants.

Main Results:

• Complex, non-linear linkage disequilibrium patterns were observed across large regions of the CETP gene.
• Known functional SNPs were associated with HDL-C, with evidence for previously uncharacterized functional SNPs.
• A promoter SNP at position -4,502, altering a transcription factor binding site, was strongly associated with HDL-C and likely functional.

Conclusions:

• Dense genotyping of CETP and its regulatory regions reveals complex genetic architecture influencing HDL-C.
• Identification of novel functional SNPs, particularly a promoter variant, refines understanding of CETP's role in lipid metabolism.
• Cross-ethnic comparisons are crucial for pinpointing functionally significant CETP variants impacting HDL-C levels.