Inflammatory bowel disease genetics and pharmacogenetics: An overview

Abstract

In the last decade significant advances in the field of IBD genetics
have taken place and various putative loci of genetic
susceptibility to IBD have been identified. Since the discovery
in 2001 of the only confirmed Crohn's disease susceptibility
gene (CARD15/NOD2), various other genes have been
extensively investigated with conflicting results. Apart from
a risk haplotype in chromosome 5 no other widely confirmed
associations with IBD have been discovered. Pharmacogenetics
is the study of the relation between genetic variability
and variability in drug response or toxicity. Pharmacogenetic
studies examined the role of gene variations in the
treatment of IBD patients with sulphasalazine, mesalazine,
methotrexate, thiopourines, corticosteroids and infliximab
but the only discovery partially translated into clinical use is
the relation between TPMT gene polymorphisms and hematological
toxicity of thiopourines. At present the application
of genetic testing in routine clinical practice for the diagnosis
and treatment of IBD seems premature and cannot be recommended.
Perhaps in the future a panel of genetic markers
will be put into clinical use in order to predict the diseases's
course, complications and response to therapy.
Key Words: ulcerative colitis, Crohn's disease, inflammatory
bowel disease, genetics, pharmacogenetics, susceptibility
genes.