Original ResearchFull Report: Basic and Translational—Alimentary TractVariants in Nicotinamide Adenine Dinucleotide Phosphate Oxidase Complex Components Determine Susceptibility to Very Early Onset Inflammatory Bowel Disease
Section snippets
Methods
All results are presented according to the Strengthening the Reporting of Genetic Associations guidelines.16 Two complementary approaches were carried out to define the genetic association of the NADPH oxidase genes (cytochrome b light chain and encodes p22phox protein [CYBA], cytochrome b-245 or NADPH oxidase 2 and encodes Nox2 or gp91phox [CYBB], NCF1, NCF2, NCF4, RAC1, RAC2) with VEOIBD (illustrated in Figure 2). The first approach used targeted exome sequencing of the NADPH oxidase gene in
Targeted Exome Sequencing
To capture rare and novel variants, we carried out targeted exome sequencing of the NADPH oxidase genes (CYBA, CYBB, NCF1, NCF2, NCF4, RAC1, RAC2; Figure 1) in 122 VEOIBD patients without any clinical or laboratory evidence of CGD (as described in Methods and reported according to the Strengthening the Reporting of Genetic Associations guidelines16). All identified NADPH oxidase mutations were heterozygous and validated using both Sanger sequencing and Taqman and compared with 480 healthy
Discussion
Overall, through targeted exome sequencing, we identified heterozygous SNPs and novel variants in the NADPH oxidase complex genes in VEOIBD patients with either impaired ROS production, reduced protein binding, or reduced gene expression. CGD is an X-linked or autosomal recessive disease in which the vast majority of mutations are found in NOX2 (Figure 1B), and almost all identified mutations are associated with markedly reduced, or absence of, the protein expression, or rare missense variants
Acknowledgments
The authors thank the all patients and their families described here.
The following authors were part of the International Early Onset Pediatrics IBD Cohort Study (www.NEOPICS.org): Sandeep S. Dhillon, Ramzi Fattouh, Abdul Elkadri, Ryan Murchie, Thomas Walters, Conghui Guo, David Mack, Hien Q. Huynh, Anne M. Griffiths, Scott B. Snapper, John H. Brumell, and Aleixo M. Muise.
References (43)
- et al.
Colitis in chronic granulomatous disease
Gastroenterology
(1982) - et al.
The age of gene discovery in very early onset inflammatory bowel disease
Gastroenterology
(2012) - et al.
Chronic granulomatous disease caused by a deficiency in p47(phox) mimicking Crohn's disease
Clin Gastroenterol Hepatol
(2004) - et al.
A new genetic subgroup of chronic granulomatous disease with autosomal recessive mutations in p40 phox and selective defects in neutrophil NADPH oxidase activity
Blood
(2009) - et al.
Single nucleotide polymorphisms that increase expression of the guanosine triphosphatase RAC1 are associated with ulcerative colitis
Gastroenterology
(2011) Specificities of inflammatory bowel disease in childhood
Best Pract Res Clin Gastroenterol
(2004)- et al.
Defective acute inflammation in Crohn's disease: a clinical investigation
Lancet
(2006) - et al.
Mutations in tetratricopeptide repeat domain 7A result in a severe form of very early onset inflammatory bowel disease
Gastroenterology
(2014) - et al.
Inflammatory bowel disease in CGD reproduces the clinicopathological features of Crohn's disease
Am J Gastroenterol
(2009) - et al.
Colitis in chronic granulomatous disease
Arch Dis Child
(2001)
Pediatric modification of the Montreal classification for inflammatory bowel disease: the Paris classification
Inflamm Bowel Dis
Increasing incidence of paediatric inflammatory bowel disease in Ontario, Canada: evidence from health administrative data
Gut
Host-microbe interactions have shaped the genetic architecture of inflammatory bowel disease
Nature
Genome-wide meta-analysis increases to 71 the number of confirmed Crohn's disease susceptibility loci
Nat Genet
Meta-analysis identifies 29 additional ulcerative colitis risk loci, increasing the number of confirmed associations to 47
Nat Genet
NADPH oxidase complex and IBD candidate gene studies: identification of a rare variant in NCF2 that results in reduced binding to RAC2
Gut
Genome-wide association study identifies new susceptibility loci for Crohn disease and implicates autophagy in disease pathogenesis
Nat Genet
Confirmation of association of IRGM and NCF4 with ileal Crohn's disease in a population-based cohort
Genes Immun
A novel nonsense mutation in the EpCAM gene in a patient with congenital tufting enteropathy
J Pediatr Gastroenterol Nutr
IL-10R polymorphisms are associated with very-early-onset ulcerative colitis
Inflamm Bowel Dis
NGESP. Exome Variant Server
Cited by (0)
Conflicts of interest The authors disclose no conflicts.
Funding This project was funded by operating grants from the Canadian Institutes of Health Research to AMM and JHB (MOP97756 and MOP119457). AMM and SS are supported by Leona M. and Harry B. Helmsley Charitable Trust to study very early onset inflammatory bowel disease. JHB held an Investigator in Pathogenesis of Infectious Disease Award from the Burroughs Wellcome Fund. Infrastructure for the Brumell Laboratory was provided by a New Opportunities grant from the Canadian Foundation for Innovation and the Ontario Innovation Trust. SBS is supported by National Institutes of Health grants HL59561, DK034854, and AI50950 and the Wolpow Family Chair in IBD Treatment and Research.
Author names in bold designate shared co-first authorship.