Epidemiological evidence for a hereditary contribution to myasthenia gravis: a retrospective cohort study of patients from North America

BMJ Open. 2020 Sep 18;10(9):e037909. doi: 10.1136/bmjopen-2020-037909.


Objectives: To approximate the rate of familial myasthenia gravis and the coexistence of other autoimmune disorders in the patients and their families.

Design: Retrospective cohort study.

Setting: Clinics across North America.

Participants: The study included 1032 patients diagnosed with acetylcholine receptor antibody (AChR)-positive myasthenia gravis.

Methods: Phenotype information of 1032 patients diagnosed with AChR-positive myasthenia gravis was obtained from clinics at 14 centres across North America between January 2010 and January 2011. A critical review of the epidemiological literature on the familial rate of myasthenia gravis was also performed.

Results: Among 1032 patients, 58 (5.6%) reported a family history of myasthenia gravis. A history of autoimmune diseases was present in 26.6% of patients and in 28.4% of their family members.

Discussion: The familial rate of myasthenia gravis was higher than would be expected for a sporadic disease. Furthermore, a high proportion of patients had a personal or family history of autoimmune disease. Taken together, these findings suggest a genetic contribution to the pathogenesis of myasthenia gravis.

Keywords: epidemiology; genetics; neurogenetics; neurology; neuromuscular disease.

Publication types

  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Autoantibodies
  • Humans
  • Myasthenia Gravis* / epidemiology
  • Myasthenia Gravis* / genetics
  • North America / epidemiology
  • Receptors, Cholinergic
  • Retrospective Studies


  • Autoantibodies
  • Receptors, Cholinergic