RASGRP1 Deficiency Manifesting as Severe Vasculopathy and Fatal Autoimmune Hemolytic Anemia

ABSTRACT Background RASGRP1 deficiency is a rare inborn error of immunity characterized by immunodeficiency, autoimmunity, and lymphoproliferation. Results We report a 5‐year‐old male with novel homozygous splice‐donor mutations in RASGRP1 (c.1720+1G>A and c.1720+2T>C) who presented with severe vasculopathy (ischemic stroke and thrombosis), secondary antiphospholipid syndrome, and fatal refractory autoimmune hemolytic anemia. Conclusion A review of 14 previously reported cases (plus current case) confirms that while infections (100%) and lymphoproliferation (87%) are common, vascular autoimmunity is an emerging life‐threatening phenotype. Hematopoietic stem cell transplantation remains the only curative therapy, as conservative management carries high mortality. Early genetic diagnosis is essential for optimal management. Trial Registration : The authors have confirmed clinical trial registration is not needed for this submission