Personalized medicine: a reality within this decade

Abstract

Personalized medicine is defined as individualized treatment based on the individual's genetic variants. Such treatment has the potential to enable pharmacogenetics, such as the prevention of 100,000 deaths per year in the USA because of adverse drug reactions or specify treatment in heart failure such at the beta 1 adrenergic receptor polymorphisms. It is claimed that coronary artery disease (CAD) is at least 50% because of genetic predisposition. Identification of the genes predisposing to CAD would greatly facilitate prevention, early treatment, and more specific therapies. The arrival of the multimillion single nucleotide polymorphism (SNP) array provides the high throughput genotyping required to perform genome-wide Association (GWA) studies. These studies require markers (SNPs) at intervals of 6,000 bp and sample size of several thousands. Platforms are available to genotype and process millions of genotypes per day. The GWA performed by the Ottawa Heart Genomic Study identified the first deoxyribonucleic acid region (9p21) predisposing to CAD after replication in six independent populations totaling 23,000. This was subsequently confirmed in several independent studies totally more than 45,000 individuals. The region confers a risk for CAD independent of known risk factors. 9p21 occurs in heterozygous form in 40 to 50% of Caucasians with increased risk of 15 to 20% and in homozygous form in 25% of Caucasians with increased risk of 40%. Identification of the genes predisposing to CAD is a prerequisite for personalized care of these patients. It is anticipated that most of the genes predisposing to CAD will be identified in the next 5 to 8 years. The 9p21, in addition to conferring increased risk, provides the bonus of being independent of known risk factors. Thus, 9p21 is likely to provide the impetus and nidus for a major research effort over the next few years. It has the potential to not only provide for early genetic screening but also as a target for novel therapy.