Neurologic Features of Immunoglobulin G4-Related Disease.

Immunoglobulin G4-related disease (IgG4-RD) can involve nearly any organ system, including the central and peripheral nervous systems. IgG4 antibodies are not known to play a primary etiologic role in disease. IgG4-RD must be distinguished from a growing number of immune-mediated conditions in which IgG4 autoantibodies contribute directly to pathophysiology. The most common neurologic features of IgG4-RD result from disease in the orbits, pachymeninges, and substance of the pituitary gland and stalk, as well as a perineuropathy that can involve peripheral or cranial nerves. Disease affecting the brain parenchyma is rare but reported.