Human Phenotype Ontology identifier HP_0008348 (Decreased circulating IgG2 concentration) is a reduction in immunoglobulin levels of the IgG2 subclass in the blood circulation. Also known as: Decreased IgG2 level in blood, Decreased circulating IgG2 level, Immunoglobulin IgG2 deficiency, Reduced IgG2 levels.