Although it has been more than five years since the draft of the human genome was first announced,^w1 only in recent months has there been substantial progress in the identification of genes that are implicated in susceptibility or cause of myocardial infarction (MI). There are many reasons for this lag, particularly related to the point that myocardial infarction is a “complex” trait. As opposed to “simple” Mendelian traits which are infrequent, deterministic and inherited in an autosomal dominant, recessive, or X-linked mode, complex traits are relatively common, probabilistic, and involve gene–gene and gene–environmental interactions. The technology and methodology to identify complex traits have rapidly evolved, and still can be considered to be in flux, with a progression from linkage studies using genome wide scanning to whole genome single nucleotide polymorphism (SNP) association studies. With this refinement in approaches, several genes are now implicated for susceptibility for myocardial infarction and one is already the subject of a dedicated randomised pharmacologic intervention trial for “personalised” medicine. This paper will review the progress in this burgeoning and important field, to provide the reader with a perspective on how genetic information will someday radically alter our approach and facilitate the prevention of heart attacks.

THE TOOLS

With a human genome that consists of 3.1 billion base pairs, finding the particular alleles that are promoting or protecting an individual to have an MI appears, on the surface, to be especially daunting. But the number of genes that comprise the genome is just over 25 000 and although the function of many has yet to be determined, the chromosomal map of the location of these genes is virtually complete. With 3.1 billion nucleotide pairs (cytosine, adenine, guanine, thymine), fortunately the inter-subject variability is rather limited to only 10 million SNPs—or 0.3% of the base pairs that are …