Abstract
Background/Aims: Occasionally, pediatric Crohn’s disease (CD) may develop after diagnosis of orofacial granulomatosis (OFG), which is characterized by chronic granulomatous lesions of the oral mucosa, lips, and perioral area. This study aimed to clarify clinical characteristics, treatment responses, and potential genetic contributors in pediatric patients with CD complicating OFG. Methods: We studied pediatric patients with CD complicating OFG who were treated from 2013 to 2022 at 7 Japanese institutions specializing in pediatric inflammatory bowel disease. Their clinical courses were analyzed retrospectively, and analyses of 71 genes associated with monogenic inflammatory bowel disease were performed. Results: Among 13 patients, 8 were girls. Median ages at diagnosis of OFG and CD were 9.2 (3.8–15.3) and 10.3 (6.4–15.3) years old, respectively. Upper gastrointestinal lesions were frequent in 8 cases (62%), while perianal lesions were present in 7 (54%). OFG failed to improve or relapsed despite remission of intestinal lesions in about half of the patients (n = 7, 54%). During follow-up, OFG went into remission in 7 patients, including 6 of the 9 who were treated with biologics (66%) and 1 of the 4 who were not (25%). In 8 patients, the NCF1 p.Arg90His allele was detected by genetic analysis; 7 were heterozygous and 1 homozygous, a higher prevalence than in the general Japanese population. Conclusions: Clinical features of OFG associated with pediatric CD are diverse, and biologic agents were beneficial for OFG patients. NCF1 p.Arg90His mutation may contribute to the pathogenesis of pediatric CD complicating OFG.