Both cases presented with thymoma combined with immunodeficiency, characterized by hypogammaglobulinemia, low or absent B lymphocytes, and decreased T-cells with inverted CD4<sup>+</sup>/CD8<sup>+</sup> T-cell ratio, while two GS patients were evaluated by endoscopy revealed mucosal edema and fine-granular or nodular appearance changes in the small intestine. The gene discussed is CD8A; the disease is immunodeficiency disease.