Genetics of inflammatory bowel disease in East Asia: From population to individual.

Abstract

Genetic analysis of inflammatory bowel disease has identified many disease susceptibility genes in a large number of cases, mainly in Europe and North America. However, because of the ethnic differences in genetic background, analysis in various ethnic groups is needed. Although genetic analysis in East Asia began at the same time as in the West, the total number of patients analyzed has remained limited in Asia. To address these issues, meta-analyses across East Asian countries are underway, and the genetic analysis of inflammatory bowel disease in East Asians is entering a new phase. New findings on the genetic background factors associated with inflammatory bowel disease originating from East Asia have also been made, such as the association between chromosomal mosaic alteration and this disease. Genetic analysis has been conducted mainly through studies that consider patients as a group. Some of these results, such as the identified relationship between the NUDT15 gene and thiopurine-related adverse events, are beginning to be applied to the actual treatment of individuals. Meanwhile, genetic analyses of rare diseases have focused on the development of diagnostic methods and therapies by identifying causative gene mutations. Recently, genetic analysis has been moving from research on populations and pedigrees to the stage of identifying and using personal genetic information of each patient, which is important for personalized medical care. To achieve this, close collaboration between specialists in complex genetic analysis and clinicians will be critical.