Lymphoid Tyrosine Phosphatase Gene Polymorphisms in Inflammatory Bowel Disease

The inflammatory bowel diseases (IBD) are chronic inflammatory disorders of the gastrointestinal tract that manifests as Crohn's disease (CD) and Ulcerative colitis (UC), clinically characterized by periods of remission interrupted by episodes of clinical disease activity (Zallot et al., 2013). Patients with IBD display some common symptoms such as severe diarrhea, pain, fatigue and weight loss , but the localization is slightly different: whereas CD affects the whole gastrointestinal tract, UC primarily affects the distal intestine and ileum (De Lange et al., 2015).

Lennard-Jones et al. have defined macroscopic and microscopic criteria to establish the diagnosis of Crohn's disease. The macroscopic diagnostic tools include physical examination, endoscopy and radiology. Microscopic features can be assessed on mucosal biopsy and/or operative specimen. The diagnosis depends on the finding of discontinuous and often granulomatous intestinal inflammation (Lennard-Jones et al., 1997). Diagnosis of ulcerative colitis is based on history, endoscopic appearances, histopathology of multiple mucosal biopsies and appropriate radiology (Silverberg et al., 2005, Satsangi et al., 2006).

The incidence pattern of UC has changed over the last two decades, with incidence continuing to rise in the West and rising incidence in previously low incidence areas such as Asia and the Middle East (0.15- 6.5 per 100,000)(Ng et al., 2017). Marked increase in UC diagnoses was noted over a 15-year period (1995-2009). In Cairo University, 17 cases were recorded in 1995-1999 and 76 cases were recorded in 2005-2009 (Esmat et al., 2014).

Both CD and UC are complex diseases genetically, in which hundreds of independent genetic loci contribute to disease susceptibility (Norouzinia et al., 2015) . Nevertheless, the molecular mechanisms and functions of many IBD associated genes remain unknown. In addition to genetics, IBDs are powerfully influenced by microbiological and environmental aspect (Norouzinia et al., 2017).

Genome-wide association studies (GWAS) have allowed a better understanding of IBD thus, several genetic susceptibility loci have been identified for UC and CD (Yamamoto-Furusho et al., 2015). Among the genetic factors involved, there are several polymorphisms in molecules of the Immune system associated with either susceptibility or protective effects to IBD progression, but even with contradictory associations, mainly depending on the onset (adult or pediatric), sample size differences and on the ethnicity-dependent genetic background (Neuman et al., 2012, Ng et al., 2012, Peng et al., 2017, Girardelli et al., 2018).