IgG Subclass Deficiency is a condition where the body does not produce enough of one or more subclasses of Immunoglobulin G (IgG), which is a type of antibody crucial for fighting infections. There are four subclasses of IgG: IgG1, IgG2, IgG3, and IgG4. Each subclass plays a specific role in the immune response, and deficiencies can lead to increased susceptibility to infections, particularly from bacteria and certain viruses. Diagnosis typically involves blood tests to measure the levels of each IgG subclass. Treatment may include immunoglobulin replacement therapy or antibiotics to prevent infections. Regular monitoring and a tailored management plan can help individuals with this deficiency maintain better health and reduce the risk of complications.