The Caspase activation and recruitment domain 11 (CARD 11 ) encodes a scaffold protein which plays an important role in multiple signaling pathways participated by antigen recognition receptors of T cells and B cells, including nuclear transcription factors, c-Jun N-terminal kinase and mammalian rapamycin target protein signaling pathway. The germline variation of CARD11 causes three different primary immunodeficiency diseases, including profound combined immunodeficiency (biallelic loss-of-function mutations), B-cell expansion with nuclear factor κB and T cell anergy (heterozygous, gain-of-function mutations) and severe atopic disease with diverse immunologic phenotypes (heterozygous, dominant negative mutations). Since the clinical manifestations of diseases caused by different CARD 11 germline variations are diverse, it is necessary to conduct functional verification experiments on rare variations to determine their pathogenicity. This article reviews the genotypes, clinical and immunophenotypes, and treatments of CARD11 variant-related diseases.