Identification of genetic variants in endothelial lipase in persons with elevated high-density lipoprotein cholesterol.
BACKGROUND
Elevated high-density lipoprotein cholesterol (HDL-C) is associated with reduced risk of cardiovascular disease, and variation in HDL-C levels has been shown to be approximately 50% heritable. Overexpression of endothelial lipase (EL), a member of the lipoprotein lipase gene family, markedly reduces HDL-C levels in mouse models. We hypothesized that genetic variation in EL might be associated with elevated HDL-C.


RESULTS
All exons and 1.2 kilobase of promoter of the EL gene were sequenced in 20 unrelated human subjects with high HDL-C levels. A total of 17 variants were identified. Six of these were potentially functional and were confirmed by restriction enzyme analysis. Four variants result in amino acid changes (Gly26Ser, Thr111Ile, Thr298Ser, and Asn396Ser,) and 2 variants were in the promoter (-303A/C and -410C/G). The genotype frequencies of each variant were determined in 176 black controls, 165 white controls, and 123 whites with high HDL-C. The Thr111Ile variant was the most common, with an allele frequency of 10.3% in blacks, 31.2% in white controls, and 32.6% in the high HDL-C group. The remaining variants all had allele frequencies <5.0% but differed in frequency among the 3 groups. Interestingly, Gly26Ser, Thr298Ser, and -303A/C were found in the black and high HDL-C white cohorts but were absent in the control white group.


CONCLUSIONS
Six new potentially functional variants in EL were discovered through sequencing of the EL gene in subjects with high HDL-C levels. Differences in allele frequencies exist between blacks and whites and between control subjects and those with high HDL-C levels.
deLemos
Andrew S
AS
Department of Medicine, University of Pennsylvania, Philadelphia, USA.
Wolfe
Megan L
ML
Long
Christopher J
CJ
Sivapackianathan
Rasheeta
R
Rader
Daniel J
DJ
D044383:Black People; D008076:Cholesterol, HDL / Q000097:blood*; D015331:Cohort Studies; D005091:Exons; D005260:Female; D005787:Gene Frequency; D014644:Genetic Variation; D006801:Humans; D008049:Lipase / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D011401:Promoter Regions, Genetic; D044465:White People
D008076:Cholesterol, HDL; C410382:LIPG protein, human; D008049:Lipase