Importance of early detection of infantile inflammatory bowe
Infantile inflammatory bowel disease (IBD) is an extremely rare subgroup of IBD that includes patients whose age of onset is younger than 2 years old. These patients can have more surgical interventions, and a severe and refractory disease course with higher rates of conventional treatment failure. Monogenic defects play an important role in this subgroup of IBD, and identification of the underlying defect can guide the therapeutic approach.

A 4-month-old girl from a nonconsanguineous family presenting with anal fistula, chronic diarrhea, and failure to thrive. She underwent multiple surgical repairs but continued to have persistent colitis and perianal fistulas. Crohn's disease was confirmed by endoscopic and histologic finding.

Conventional pediatric IBD therapy including multiple surgical interventions and antitumor necrosis factor alpha agents were applied.

The patient did not respond to conventional pediatric IBD therapy. Interleukin-10 (IL-10) receptor mutation was discovered by whole-exome sequencing and defective IL-10 signaling was proved by functional test of IL-10 signaling pathway by the age of 12. The patient is currently awaiting hematopoietic stem cell transplantation.

Early detection of underlying genetic causes of patients with infantile-IBD is crucial, since it may prevent patients from undergoing unnecessary surgeries and adverse effects from ineffective medical therapies. Moreover, infantile-IBD patients with complex perianal disease, intractable early onset enterocolitis and extraintestinal manifestations including oral ulcers and skin folliculitis, should undergo genetic and functional testing for IL-10 pathway defect.