Coronary artery disease (CAD) is the most prevalent disorder and the leading cause of death worldwide. There are a number of CAD medications, which are effective and safe in most patients, but have been associated with adverse reactions such as angioedema induced by angiotensin I-converting enzyme inhibitors (AE-ACEi). In this study, we identified aminopeptidase P (APP) activity as an endophenotype for AE-ACEi, which is a heritable quantitative trait (heritability =0.336 +/- 0.251 SD) and is significantly reduced in a majority of our cases. Although initial mutation screening did not reveal any coding variants in XPNPEP2, which encodes membrane-bound APP, subsequent linkage analysis of APP activity in eight families provided a maximum LOD score (3.75) for this locus. Sequencing of additional cases identified a splice variant (314_431del) and a non-coding polymorphism (rs3788853) in this locus, which cosegregate with low plasma APP activity. The latter accounts for the linkage signal and is associated with AE-ACEi (P = 0.036). In addition, we identified other potential loci for APP activity and demonstrated that certain ACEi (Captopril and Enalapril) non-specifically inhibit APP activity. Furthermore, we detected polymorphisms associated with reduced APP and ACE activities among females with estrogen-dependent inherited angioedema. / We also conducted a genetic investigation of depression among CAD patients to identify common susceptibility loci which might explain the correlation between these diseases. Our candidate gene association study identified a polymorphism (rs216873) in the von Willebrand factor gene that was significantly associated (P = 7.4 x 10-5) with elevated depressive symptoms in our CAD cohort. These results suggest that risk factors for atherosclerosis also underlie susceptibility to depression among CAD patients. / This dissertation contributes to the field of genetics and pharmacogenomics of CAD. A better understanding of the toxic effects of CAD drugs will assist in the development of safer and more effective treatments. In addition, our results may facilitate clinical assays to identify individuals who are susceptible to angioedema prior to ACEi or estrogen therapy. Finally, our genetic investigation of depression in CAD patients reveals a novel drug target (VWF) for treatment of depression in cardiac cases.

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