Tehran University of Medical Sciences Immunology and Genetics Journal 2645-4831 6 1 2023 03 22 34 38 Saba Fekrvand Research Center for Immunodeficiencies, Children’s Medical Center, Tehran University of Medical sciences Mohammad Shahrooei Department of Microbiology and Immunology, Clinical and Diagnostic Immunology, KU Leuven, Leuven, Belgium. Mahnaz Sadeghi_Shabestari Immunology Research Center, TB and Lung Disease Research Center of Tabriz, Tabriz University of Medical Science, Tabriz, Iran. 2024 06 30 2024 07 18 Herein we report a novel case of SHORT syndrome with very early onset inflammatory bowel disease (VEO- IBD). He presented with hematochezia since the first months of life for which he was diagnosed with cow milk allergy that did not respond to treatment. He underwent a colonoscopy confirming the diagnosis of ulcerative colitis (UC). His past medical history was also remarkable with delayed growth since 6 months of age and frequent hospitalizations due to recurrent fever, gastroenteritis, and anemia with no history of recurrent infectious episodes. Despite appropriate treatment for UC and partial improvement in his bowel habits and nutrition, there was no improvement in his growth status and he was found to have failure to thrive. The patient further underwent genetic test evaluation and a novel heterozygous missense mutation was detected in the PIK3R1 gene (c.2076A>C, P. Lys692Asn) confirming the diagnosis of SHORT syndrome. He got appropriate treatment and is currently doing well, in good condition and is under regular monthly follow-up. https://igj.tums.ac.ir/index.php/igj/article/view/138 https://igj.tums.ac.ir/index.php/igj/article/download/138/116