Coronary artery disease (CAD) and myocardial infarction (MI) are polygenic disorders caused by a complex interaction between environmental and genetic factors. A family history of MI is also an independent risk factor for MI.¹ Several methods have been proposed to identify the underlying genetic cause of CAD, including genetic linkage studies and candidate gene approaches.

CAD and MI are the clinical manifestations of underlying coronary atherosclerosis. The cornerstones of this process are elevated plasma lipid concentrations and inflammation. Central to this process is the relation between endothelial cells (EC) and smooth muscle cells (SMC). Connexins are members of a multigene gap junction family that may mediate EC-SMC communication. These transmembrane channels connect neighbouring cells allowing movement of small molecules and second messengers.²

The role of connexin 37 (CX37) and the C1019T polymorphism have been previously investigated in CAD and MI. The functional impact of the C1019T single nucleotide polymorphism has not been determined but it does result in a change in the amino acid sequence (Pro319Ser). A genome-wide search for susceptibility genes for MI identified a novel susceptibility locus on chromosomal region 1p34–36.³ This region contains the gene coding for CX37. The T allele of the C1019T polymorphism has been found to be significantly associated with the risk of MI in men and with CAD in high risk males,⁴ defined as those with hypertension, diabetes mellitus, …