Immunoglobulin G sublass deficiency is defined as a decrease of an IgG sublass greater than 2 standard deviations below the normal mean for age. One or more IgG subclasses and other Ig isotypes may be involved. This deficiency may be isolated or associated with other immunodeficiencies (IgA deficiency, ataxia-telangiectasia).
- Deficiencies predominantly affecting antibody production
- Selective deficiency of IgG subclass, IgE and/or IgA class or subclass