A Novel Variant of CORO1A Gene Contributing to the Development of Primary Immunodeficiency in Children

Introduction The case report describes a novel finding of a homozygous variant in the coronin 1A (CORO1A) gene, associated with atypical severe combined immunodeficiency (SCID) in a 9‐year‐old female patient with recurrent infections and unique immunological features, including periodic T‐cell lymphocytosis and T‐ and B‐cell lymphopenia. Case History and Examination A 9‐year‐old female with a known history of recurrent pneumonia presented to the emergency department with a 2‐week history of intermittent fever, progressive lethargy, and pallor. Her past medical history was remarkable for multiple hospital admissions secondary to community‐acquired pneumonia and urinary tract infections, totaling four admissions to date. Family history was significant for consanguinity between parents and a healthy 4‐year‐old younger male sibling. Chest computed tomography (CT) demonstrated bilateral diffuse centrilobular nodules, scattered ground‐glass opacities, and left lower lobe consolidation, in addition to a tree‐in‐bud pattern. Immunological evaluation revealed T‐cell lymphocytosis, B‐cell lymphopenia, and a decreased CD4/CD8 ratio. Based on these findings, the pediatric allergy and immunology team recommended genetic testing for primary immunodeficiency. The panel identified a homozygous variant of uncertain significance (VUS) in the CORO1A gene. Pathogenic variants in CORO1A are associated with autosomal recessive CORO1A‐related SCID. Conclusion The novel homozygous variant in the CORO1A gene suggests the likelihood of an atypical form of SCID, characterized by periodic T‐cell lymphocytosis, T‐cell lymphopenia, B‐cell lymphopenia, and a low CD4/CD8 ratio, expanding the spectrum of CORO1A deficiency.