Pharmacogenomics and Coagulation Disorders

The term pharmacogenetics, first introduced by Vogel in 1959 (1 ) is defined as the analysis of inherited factors that define an individual’s response to a drug, and generally refers to monogenetic variants that affect drug response. Pharmacogenetics refers to the monogenetic variants that affect drug response, and aims to deliver the right drug to the correct patient at the correct dosage by using DNA information. Pharmacogenomics refers to the entire library of genes that determine drug efficacy and safety. There are approx 3 billion basepairs in the human genome, which code for at least 30,000 genes. Although the majority of basepairs are identical from individual to individual, only 0.1% of the basepairs contribute to individual differences. Three consecutive basepairs form a codon that specifies the amino acids that constitute the protein, because of substantial redundancy, and two or more codons code for the same amino acid. Genes represent a series of codons that specifies a particular protein. At each gene locus, an individual carries two alleles—one from each parent. If there are two identical alleles, it is referred to as a homozygous genotype; if the alleles are different, it is heterozygous. Genetic variations usually occur as single-nucleotide polymorphisms (SNP) on average at least once every 1000 basepairs, accounting for approx 3 million basepairs distributed throughout the entire genome. Genetic variations that occur at a frequency of at least 1% in the human population are referred to as polymorphisms.