Familial autoimmune myasthenia gravis: Four patients involving three generations

Background: Familial autoimmune myasthenia gravis (MG) is rare, although a genetic role for the development of autoimmune MG is suggested by concordan ce in monozygotic twins and the increased frequency of other autoimmune dis eases in family members of myasthenics. Methods: A patient with a family hi story of MG was evaluated in hospital. Relatives were interviewed and medic al records examined for details regarding the diagnosis of MG in three othe r family members. Results: The index case first experienced symptoms of MG at age 75 years. She developed generalized MG and required corticosteroids and immunosuppressive therapy to control her disease, Her father developed predominantly bulbar symptoms of MG at age 75 years. He died of complicatio ns experienced following a gastrostomy placed for continued difficulty swal lowing, His brother developed similar symptoms of MG in his early 60s and d ied shortly after thymectomy. A 46-year-old nephew of the index case is als o beginning to exhibit signs of generalized MG. Acetylcholine receptor anti bodies were strongly positive in the index case and her nephew. (The assay was not available for her Father and uncle). Conclusions: Four individuals in three successive generations had diagnoses of autoimmune MG. Study of fa milial cases such as these may clarify the contribution of genetic factors to the development of this disease.