PIK3CD and immunodeficiency disease: APDS, which is also known as PASLI disease (p110 δ-activating mutation causing senescent T cells, lymphadenopathy, and immunodeficiency), are combined immunodeficiencies resulting from GOF mutations in the genes PIK3CD and PIK3R1 encoding the subunits of phosphoinositide 3-kinase δ (PI3Kδ) and p85α, the regulatory subunit of PI3K [74,75].