The most frequently identified genetic alteration in our cohort was the TACI mutation, followed by mutations in DOCK8, RAG1, LRBA, PRF1, PSTPIP1, CECR1, PRKDC, and MRTFA. TACI mutations are widely recognized as key contributors to immune dysregulation in IEIs, particularly in CVID. This evidence concerns the gene RAG1 and common variable immunodeficiency.