K.K. Jain, Textbook of Personalized Medicine, DOI 10.1007/978-1-4939-2553-7_5, 149
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Chapter 5
Pharmacogenomics
Introduction
The total genetic material of an organism, that is, an organism’s complete
deoxyribonucleic acid (DNA) sequence is called a genome and genomics is the
study of all of the genes in an organism – their sequences, structure, regulation,
interaction, and products. Currently, it is estimated that there are approximately
19,000 genes in the human organism. Several new technologies have been devel-
oped to study the genome and new terms have been derived from genomics, the best
known of which is pharmacogenomics. Completion of sequencing of the human
genome has opened a new era for improved understanding of the genetic basis of
human diseases and to provide new targets for drug discovery. Pharmacogenomics
is an important basis for the development of personalized medicines.
Pharmacogenomics implies the use of genetic sequence and genomics informa-
tion in patient management to enable therapy decisions. The genetic sequence and
genomics information can be that of the host (normal or diseased) or of the patho-
gen. Pharmacogenomics will have an impact on all phases of drug development –
from drug discovery to clinical trials. It will also apply to a wide range of therapeutic
products including bioengineered proteins, cell therapy, antisense therapy and gene
therapy. These treatments are also subject to constraints and complexities engen-
dered by individual variability. Role of pharmacogenomics in variable therapy tar-
gets is shown in Table 5.1.
Basics of Pharmacogenomics
Pharmacogenomics applies the large-scale systemic approaches of genomics to
drug discovery and development. It also involves the study of the mechanisms by
which drugs change the expression of genes, including drug-metabolizing enzymes,
a phenomenon known as induction. Various technologies enable the analysis of