Coronary heart disease (CHD) is a major public health concern, affecting almost 16 million people in the U.S. and leading to 452,300 deaths in 2004 alone. Low levels of high density lipoprotein (HDL) cholesterol have been shown to increase the risk for cardiovascular disease (CVD). The role of genetics in affecting total cholesterol, HDL-cholesterol, and triglycerides levels is significant, with heritability estimates exceeding 50%. Recent studies have identified major loci associated with HDL-cholesterol through genome-wide association studies, which investigated influences of common variants on common traits. Relatively few studies have investigated the impact of rare variants (or common variants with a modest affect) on common disease. The aim of our study was to evaluate the genetic variation in APOA2 (a biological candidate gene involved in HDL metabolism) in relation to HDL-cholesterol levels in epidemiological samples of African Blacks and U.S. Non-Hispanic Whites (NHWs). We resequenced APOA2 in individuals with HDL-cholesterol levels in the upper 5th percentile (47 NHWs and 48 Blacks) and lower 5th percentile (48 NHWs and 47 Blacks), allowing us to identify both rare and common variants. Common tagSNPs and all rare variants have been screened in the larger NHW and Black samples for associations with HDL-cholesterol levels. We detected a total of 26 variants (25 single nucleotide substitutions and 1 microsatellite); 12 of which were previously unreported. Of the 12 new variants, 6 were present in NHWs and 6 in Blacks. We observed an increased number of minor alleles of APOA2 variants (either increased heterozygosity for rare variants or increased homozygosity for common variants) in subjects with low HDL levels, more pronounced in NHWs. We performed a preliminary analysis using a total of 9 variants that were screened in NHWs (n=624, 8 variants) and Blacks (n=788, 5 variants) with TaqMan SNP genotyping assays to date. For the 8 variants that were screened in NHWs, we found significant association in only females for variants 2233C>T/rs6413453 (p=0.028) and 3251A>G (p=0.023). Completing genotyping for remaining variants will allow us to determine the extent to which APOA2 variants influence HDL levels.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-04112008-112445 |
| Date | 26 June 2008 |
| Creators | Hollister, Sally Marie |
| Contributors | David N. Finegold, M.D., F. Yesim Demirci, M.D., M. Ilyas Kamboh, Ph.D. |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-04112008-112445/ |
| Rights | restricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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