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Purpose: Pediatric inflammatory bowel disease (IBD) is a heterogeneous disorder caused by multiple factors. Although genetic and immunological analyses are required for a definitive diagnosis, no reports of a comprehensive genetic study of a Japanese population are available. Methods: In total, 35 Japanese patients <16 years of age suffering from IBD, including 27 patients aged <6 years with very early-onset IBD, were enrolled in this multicenter study. Exome and targeted gene panel sequencing was performed for all patients. Mutations in genes responsible for primary immunodeficiency diseases (PID) and clinical and immunological parameters were evaluated according to disease type. Results: We identified monogenic mutations in 5 of the 35 patients (14.3 %). We identified compound heterozygous and homozygous splice-site mutations in interleukin-10 receptor A ( IL- 10RA) in two patients, nonsense mutations in X-linked inhibitor of apoptosis protein ( XIAP) in two patients, and a missense mutation in cytochrome b beta chain in one patient. Using assays for protein expression levels, IL-10 signaling, and cytokine production, we confirmed that the mutations resulted in loss of function. For each patient, genotype was significantly associated with clinical findings. We successfully treated a patient with a XIAP mutation by allogeneic cord blood hematopoietic stem cell transplantation, and his symptoms were ameliorated completely. Conclusions: Targeted sequencing and immunological analysis are useful for screening monogenic disorders and selecting curative therapies in pediatric patients with IBD. The genes responsible for PID are frequently involved in pediatric IBD and play critical roles in normal immune homeostasis in the gastrointestinal tract. [ABSTRACT FROM AUTHOR]

Background: X-linked inhibitor of apoptosis protein (XIAP) deficiency is a rare immunodeficiency that is characterized by recurrent hemophagocytic lymphohistiocytosis (HLH) and splenomegaly and sometimes associated with refractory inflammatory bowel disease (IBD). Although hematopoietic stem cell transplantation (HSCT) is the only curative therapy, the outcomes of HSCT for XIAP deficiency remain unsatisfactory compared with those for SLAM-associated protein deficiency and familial HLH. Aim: To investigate the outcomes and adverse events of HSCT for patients with XIAP deficiency, a national survey was conducted. Methods: A spreadsheet questionnaire was sent to physicians who had provided HSCT treatment for patients with XIAP deficiency in Japan. Results: Up to the end of September 2016, 10 patients with XIAP deficiency had undergone HSCT in Japan, 9 of whom (90%) had survived. All surviving patients had received a fludarabine-based reduced intensity conditioning (RIC) regimen. Although 5 patients developed post-HSCT HLH, 4 of them survived after etoposide administration. In addition, the IBD associated with XIAP deficiency improved remarkably after HSCT in all affected cases. Conclusion: The RIC regimen and HLH control might be important factors for successful HSCT outcomes, with improved IBD, in patients with XIAP deficiency. [ABSTRACT FROM AUTHOR]

To determine the prevalence and clinical characteristics of patients with in Japan, we conducted a nationwide survey of primary immunodeficiency disease (PID) patients for the first time in 30 years. Questionnaires were sent to 1,224 pediatric departments and 1,670 internal medicine departments of Japanese hospitals. A total of 1,240 patients were registered. The estimated number of patients with PID was 2,900 with a prevalence of 2.3 per 100,000 people and homogenous regional distribution in Japan. The male-to-female ratio was 2.3:1 with a median age of 12.8 years. Adolescents or adults constituted 42.8% of the patients. A number of 25 (2.7%) and 78 (8.5%) patients developed malignant disorders and immune-related diseases, respectively, as complications of primary immunodeficiency disease. Close monitoring and appropriate management for these complications in addition to prevention of infectious diseases is important for improving the quality of life of PID patients. [ABSTRACT FROM AUTHOR]

Presents information on a case report about novel JAK3 mutation in a Japanese patient with severe combined immunodeficiency. Results of the JAK3 genomic DNA and complementary DNA analyses; Scientific method used for the detection of JAK3; Discussion on the diagnosis of the patient with intersitial pneumonia.

Background Ataxia telangiectasia (A-T) is a common inherited cause of early childhood-onset ataxia, distinguished by progressive cerebellum malfunction, capillary vessel extension, and immunodeficiency. The diagnosis of A-T is sometimes difficult to establish in patients with atypical clinical evolution. Case report We experienced a pediatric 12-years-old female patient, who was finally diagnosed with classic A-T, demonstrating progressive dystonic-myoclonic axial jerks with ataxia as a predominant clinical feature. Oculocutaneous telangiectasias and immune status were unremarkable. Her myoclonic jerks were spontaneous or stimulus-sensitive, and partially ameliorated by levodopa treatment, but the ataxia was slowly progressive. A laboratory examination showed moderate atrophy of the vermis and cerebellum on brain magnetic resonance imaging, elevated serum alpha fetoprotein (AFP) levels, and total absence of A-T mutated (ATM) protein activity. We subsequently confirmed compound heterozygous truncating mutations of the ATM gene in this patient. Conclusion Our findings highlight the importance of recognizing dystonic-myoclonic jerks as one of the extrapyramidal signs of classic A-T. Measurement of AFP levels should be considered in patients with unexplained myoclonic jerk movements with ataxia in whom definitive diagnoses are not identified. Physicians should be aware that there are cases where typical findings of A-T may not be fulfilled. [ABSTRACT FROM AUTHOR]