Analysing downstream effects of monogenic disorders causing CAD using the Affymetrix GeneChip system

Harald Funke

Institut für Klinische Chemie und Laboratoriumsmedizin, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Str. 33, D-48145 Münster, Germany (Tel: +49 251 83 56209, Fax: +49 251 83 56208, E-mail: gene@uni-muenster.de)

Atherosclerotic vascular diseases are important factors for morbidity and death in developed countries. It is likely that with increasing wealth, the incidence of atherosclerotic disease will also increase in the emerging nations.
Current programs for risk reduction are primarily targeted towards changes in lifestyle factors. Family and twin studies have shown, however, that a major portion of cardiovascular risk can be assigned to genetic factors. In rare cases, as in homozygous familial hypercholesterolemia, a single gene defect alone causes early onset coronary artery disease (CAD). More often, myocardial infarction, stroke, diabetic vasculopathy and other forms of atherosclerosis arise from the interaction between several genes of small effect (polygenes) and adverse environmental factors. In myocardial infarction occurring at young age gene defects may be the leading causative factors. Despite such a prominent role of genetics in the pathophysiology of atherosclerosis clinical risk assessment and therapeutic decision making are still based on classical risk factors. This is largely due to current limitations in the detection of genetic variation in large population samples.
        A major obstacle in the assessment of the role SNPs have in the prediction of CAD has been the difficulty to cluster the phenotypic effects of SNPs from a large number of genes in an unbiased fashion. Gene expression data provide a summary the effects the interaction of various genes and their variants have with each other and also with external factors, such as individual lifestyle habits. The analysis of such a synopsis with gene chip technology allows the use of much simpler mathematical models for data analysis. Expression profiling is therefore seen as a potentially very helpful tool in the early detection and classification of CAD and thus offers the potential to be an invaluable aid for therapeutic decision making.
        We have characterized expression profiles from carriers of monogenic disorders which are tightly associated with premature CAD formation and compared them to profiles from controls. This identified potential downstream mediators of the vascular processes leading to atherosclerosis.