BACKGROUND & AIMS:Advances in genomic technologies have led to increasing reports of monogenic inflammatory bowel disease (IBD). Here, we systematically review the literature to determine the clinical features, genetic profile, and previously used treatment strategies in monogenic IBD. METHODS:A systematic review of MEDLINE articles published between January 2000 and December 2020 was conducted. A total of 750 individual monogenic IBD cases were identified from 303 eligible articles. RESULTS:The most frequently reported monogenic IBD genes were IL10RA/B, XIAP, CYBB, LRBA, and TTC7A. In total, 63.4% of patients developed IBD before 6 years of age, 17.4% developed IBD between ages 10 and 17.9 years, and 10.9% developed IBD after age 18. There was a substantial difference between these age groups and the underlying monogenic disorders. Only 31.7% had

Background To evaluate the role of colonoscopy in infants and young children and clarify the distribution of colonoscopy-requiring diseases in this age group. Methods Cohorts of colonoscopies performed at three children’s hospitals in Japan between April 2011 and March 2016 including infants and children younger than six years of age were retrospectively reviewed. Results In total, 453 colonoscopies were performed in 276 infants and young children. Of these 275 (60.8%) were for diagnostic purposes, 177 (39.2%) were performed as follow-up, and one case was performed for treatment. The median patient age at the time of diagnostic colonoscopy was 2.49 years, and there was a male-to-female ratio of 1.72:1. Abnormal macroscopic and/or histopathological findings were noted in 212 (77.1%) cases. Of these, definite diagnoses were established for the presence of eosinophilic gastrointestinal disorders (EGIDs), inflammatory bowel disease (IBD), and polyp/polyposis in 23, 18.5, and 14% of patients, respectively. Among 51 IBD cases, ulcerative colitis, Crohn’s disease, and IBD-unclassified were identified in 47.1, 33.3, and 7.8%, retrospectively via endoscopic examination. Of these, 11 (22%) were eventually diagnosed with monogenic diseases via genetic testing. Of those with rectal bleeding, EGIDs, polyps/polyposis, and IBD were found in 27, 19, and 18%, retrospectively. There were significantly more cases of EGIDs and fewer ones of IBD and polyps/polyposis in patients with rectal bleeding younger than two years of age. Furthermore, 68% of all follow-up colonoscopies were performed in children with IBD. There were no serious complications in our study cohort. Conclusion We determined the role of colonoscopy in infants and young children. Diseases diagnosed using colonoscopy in this age group included IBD, EGIDs, and polyps/polyposis. The increasing trend of patients with IBD and EGIDs worldwide means that the role of colonoscopy in infants and younger children will be more important in the future.

Background/Aims: There are few published registry studies from Asia on pediatric inflammatory bowel disease (IBD). Registry network data enable comparisons among ethnic groups. This study examined the characteristics of IBD in Japanese children and compared them with those in European children.Methods: This was a cross-sectional multicenter registry study of newly diagnosed Japanese pediatric IBD patients. The Paris classification was used to categorize IBD features, and results were compared with published EUROKIDS data.Results: A total of 265 pediatric IBD patients were initially registered, with 22 later excluded for having incomplete demographic data. For the analysis, 91 Crohn’s disease (CD), 146 ulcerative colitis (UC), and 6 IBD-unclassified cases were eligible. For age at diagnosis, 20.9% of CD, 21.9% of UC, and 83.3% of IBD-unclassified cases were diagnosed before age 10 years. For CD location, 18.7%, 13.2%, 64.8%, 47.3%, and 20.9% were classified as involving L1 (ileocecum), L2 (colon), L3 (ileocolon), L4a (esophagus/stomach/duodenum), and L4b (jejunum/proximal ileum), respectively. For UC extent, 76% were classified as E4 (pancolitis). For CD behavior, B1 (non-stricturing/non-penetrating), B2 (stricturing), B3 (penetrating), and B2B3 were seen in 83.5%, 11.0%, 3.3%, and 2.2%, respectively. A comparison between Japanese and European children showed less L2 involvement (13.2% vs. 27.3%, <i>P</i>< 0.01) but more L4a (47.3% vs. 29.6%, <i>P</i>< 0.01) and L3 (64.8% vs. 52.7%, <i>P</i>< 0.05) involvement in Japanese CD children. Pediatric perianal CD was more prevalent in Japanese children (34.1% vs. 9.7%, <i>P</i>< 0.01).Conclusions: Upper gastrointestinal and perianal CD lesions are more common in Japanese children than in European children.

Background Biliary atresia (BA) is among the commonest indications for liver transplantation (LT) in children. We examined whether serum matrix metalloproteinase‐7 (MMP‐7) is useful for diagnosis of BA in Japanese infants, and whether serum MMP‐7 concentrations before and after Kasai portoenterostomy (KP) predicted LT within a year. Methods Subjects under 6 months old at eight pediatric centers in Japan were enrolled retrospectively, including patients with cholestasis and normal controls (NC) without liver disease. Patients with cholestasis were divided into groups representing BA versus cholestasis from other causes (non‐BA). Serum samples were collected from patients with BA at diagnosis and 1 and 4 weeks after KP, as well as from non‐BA and NC. Results Serum MMP‐7 concentrations were significantly higher in BA at diagnosis (median, 89.1 ng/ml) than in non‐BA (11.0; p < 0.001) or NC (10.3; p < 0.001). Receiver operating characteristic (ROC) analysis of MMP‐7 for BA versus non‐BA yielded an area under the ROC curve of 0.99 (95% confidence interval, 0.96–1.00). An optimal cut‐off value of 18.6 ng/ml for serum MMP‐7 in diagnosing BA demonstrated sensitivity and specificity of 100% and 90%, respectively. Serum MMP‐7 before and 1 week and 4 weeks after KP did not differ significantly between BA requiring only KP and BA requiring LT after KP. Conclusion Serum MMP‐7 is a useful marker for diagnosis of BA in Japanese infants, but it could not predict LT within a year.

To our knowledge, this is the first multicenter study of zinc monotherapy for young children with presymptomatic Wilson disease. Such monotherapy proved highly effective and safe. Maintaining normal transaminase values (or values under 50 U/L when normalization is difficult) and 24-h urinary copper excretion between 1 and 3 μg/kg/day and under 75 μg/day is a reasonable goal. An initial dose of 50 mg/day is appropriate for patients under 6 years old.