Very early onset inflammatory bowel disease (IBD) may be caused by defects to the NADPH oxidase complex, as well as result in the immune cells’ inability to kill bacteria in the intestine, as suggested by a recent study conducted at The Hospital for Sick Children (SickKids) and published in the September issue of the Gastroenterology journal, entitled, “Variants in Nicotinamide Adenine Dinucleotide Phosphate Oxidase Complex Components Determine Susceptibility to Very Early Onset Inflammatory Bowel Disease.” The study, which analyzed data from children diagnosed between 1994 and 2012, may give clues to a more individualized and effective treatment for young children suffering from the disease.

In order to understand the relationship between the defective genes that cause the genetic illness chronic granulomatous disease (CGD) and the young patients observed by the physicians at the hospital, the research team led by Dr. Aleixo Muise, co-director of the SickKids IBD Centre and Clinician-Scientist at SickKids, conducted a targeted exome sequencing on the genes that encode NADPH oxidase complex in 122 patients with IBD diagnosed at SickKids from 1994 to 2012.

The conclusions of the study revealed that one third of the patients registered defects in the genes that encode the NADPH pathway, and that these defects in the genes resulted in the immune cells’ inability to kill bacteria in the intestine, according to the research, which was supported by Canadian Institutes of Health Research (CIHR) and Leona M. and Harry B. Helmsley Charitable Trust to study Very Early Onset IBD.

“Understanding the root cause of IBD in an individual patient, or patient population, is critical to treating their disease. Our finding points to how we can tailor therapy to the specific genetic changes that impact the body’s ability to kill bacteria in the gut,” stated Muise, also an Associate Professor in the Department of Pediatrics at the University of Toronto.

“The big goal is to provide precise medicine to our patients, and this is a great example of a patient population where we think it is possible to go from genetic discovery to novel therapeutic relatively quickly,” he added. The scientists are now planning on performing further studies to closely analyze the NADPH pathway to see if it is also involved in older children with IBD as well as in kids with rheumatoid arthritis.

Infantile IBD is a severe form the disease and strikes at a very early age, usually before six year old. Symptoms include inflammation of the colon and it is similar to the genetic illness chronic granulomatous disease (CGD). CGD is also a result of defects to the NADPH oxidase complex, causes a reduction of the immune system cells’ capacity to kill bacteria in the body and, in 40% of the cases, it also results in the development of Crohn’s disease, other sever IBD.