Introduction

Abstract

Inflammatory bowel disease (IBD), comprised largely of ulcerative colitis (UC) and Crohn’s disease (CD), is a complex, polygenic, heterogeneous group of diseases with great variation in phenotypic expression. Due to this variation, opportunities for personalised medicine, also known as ‘precision medicine’, are afforded at practically every step of IBD management, including diagnosis, risk stratification, drug selection and optimisation and prediction and management of IBD-related complications. Central to translating the promise of personalised medicine into improved IBD management are biomarkers (Fig. 1.1). As measurable or detectable markers of biological processes, biomarkers allow the characterisation and quantification of genetic predisposition, drug metabolism and response, disease activity and adverse drug effect monitoring. Ideally, biomarkers are noninvasive, safe, cost-effective and easily used, important factors for IBD patients where endoscopy and radiological imaging are often relied upon with significant risk, expense and inconvenience. Despite their clear utility, optimally selecting biomarkers from a practically infinite number of possibilities is challenging. Rapidly evolving scientific platforms offer rich opportunities for biomarker discovery, but the associated analysis of vast data readouts can be unwieldly. This introductory section will broadly outline various approaches to biomarker discovery, with a particular view to the translation of such efforts into improved personalised medicine for IBD patients. The structure of the book will also be outlined.