Evaluation of the diagnosis and clinical characteristics of patients who followed up with the diagnosis of primary immunodeficiency in Hacettepe University Ihsan Doğramaci Children's Hospital Pediatric Immunology Department

Primary immunodeficiencies (PID) are common diseases that cause severe disease burden. Since early diagnosis is essential in reducing PID-related mortality and morbidity, clinical features of PIDs should be well known. We included 2473 patients who followed up with PID diagnosis in our clinic. We examined their age, gender; presence of concomitant autoimmune, allergic, autoinflammatory diseases or cancer, underlying genetic etiology, consanguinity, receiving IGRT, hematopoietic stem cell transplantation status. Predominantly antibody deficiencies were found to be the most common PID class with 1393 patients (56.3%). Transient hypogammaglobulinemia of infancy was found to be the most common PID with 678 patients (27,4%). Ataxia-Telangiectasia was the most common disease with 196 patients in the combined immunodeficiencies (CIDs) with syndromic features. RAG deficiencies and ADA deficiency were the most common genetic defects leading to severe CIDs. DOCK8 deficiency and MHC class 2 deficiency were the most common diseases in CIDs. Chronic granulomatous disease has the largest share in congenital phagocytic system defects, and most of the genetic defects detected in this group were inherited autosomal recessively. Griscelli syndrome, LRBA deficiency, susceptibility to EBV and lymphoproliferative conditions were the most common PIDs associated with immune dysregulation. Mendelian susceptibility to mycobacterial diseases was found to be the largest group of innate immune system defects. Hereditary angioedema was the most common complement deficiency. In conclusion; for making early diagnosis of PIDs, newborn screening programs should be expanded and PIDs importance should be emphasized during medicine and pediatrics education. It is important to educate society about risks of consanguineous marriage. Establishing a national PID registration system is important in determining education and health policies.