Combined immunodeficiency due to CD3gamma deficiency is an extremely rare genetic combined primary immunodeficiency characterized by a selective partial lymphopenia (T+/-B+NK+) phenotype and decreased CD3 complex resulting in a variable but usually mild clinical presentation ranging from asymptomatic until adulthood to high susceptibility to infections from early infancy with predominant automimmune manifestations. The disease is combined immunodeficiency due to CD3gamma deficiency (Monarch Disease Ontology identifier MONDO_0014276). Also known as: CD3 deficiency, CD3-gamma deficiency, CD3gamma deficiency, IMD17, SCID-like immunodeficiency, T cell-partial, B cell-positive, NK cell-positive, immunodeficiency 17, immunodeficiency 17, CD3 gamma deficient, immunodeficiency type 17.