The clinical and immunological manifestations of the three patients are similar but non-characteristic, therefore, genetic analysis for an inherited immunity disorder was initiated by NGS which was performed by the Human Genetic Center of Tübingen to analyze JAK3, IL2RG, ILR7, PNP, ZAP70, RFXANK, CIITA, RFX5, FOXN1, RFXAP, CD3D, CD3E, STK4, CD3G, CD247, UNC119 and CD8A genes. The gene discussed is CIITA; the disease is immune system disorder.