Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 23 4 2024 04 27 452 456 Sezin Naiboğlu Pediatric Allergy and Immunology Clinic, University of Health Basaksehir Cam and Sakura City Hospital, Istanbul, Turkey Alper Gezdirici Department of Medical Genetic, University of Health Basaksehir Cam and Sakura City Hospital, Istanbul, Turkey Selami Ulaş Pediatric Allergy and Immunology Clinic, University of Health Basaksehir Cam and Sakura City Hospital, Istanbul, Turkey Işılay Turan Pediatric Allergy and Immunology Clinic, University of Health Basaksehir Cam and Sakura City Hospital, Istanbul, Turkey Mehmet Çeliksoy Pediatric Allergy and Immunology Clinic, University of Health Basaksehir Cam and Sakura City Hospital, Istanbul, Turkey Çiğdem Aydoğmuş Department of Medical Genetic, University of Health Basaksehir Cam and Sakura City Hospital, Istanbul, Turkey 2022 12 28 2024 02 20 Agammaglobulinemia is a rare inherited immunodeficiency disorder characterized by low or absent B cells with absent immunoglobulins. While X-linked agammaglobulinemia (XLA) is the most common type other genetic forms of agammaglobulinemia have been identified. During early childhood, passively transferred maternal Immunoglobulin G protects against various infections. The depletion of these antibodies begins between 6 and 12 months of age, resulting in recurrent sinusitis, bronchitis, and pneumonia in children with X-linked agammaglobulinemia. However, less common autosomal recessive forms of agammaglobulinemia present with more severe clinical features, leading to earlier diagnosis. Herein we present the case of a two-month-old male with IGLL1 gene defect and different clinical findings of family members with the same mutation. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/3741 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/3741/2059