The patient was found to carry a novel variant, (c.58G > A p.(Val20lle)), in the PIK3CD gene.<h4>Conclusions</h4>We describe a 3-year-old patient with a novel variant in the PIK3CD gene (c.58G > A p.(Val20lle)) presenting with EBV viremia, Hodgkin lymphoma, upregulation T follicular helper cells and CD10 + B cells consistent with a phenotype of APDS in a 3-year-old boy. Here, MME is linked to activated PI3K-delta syndrome.