Myasthenia gravis (MG) has a global prevalence of 15-179 people per million. In about 86% of cases, weakness in the eyes is the first symptom. Patients that only experience eye-related MG symptoms have ocular MG. Many patients that have ocular MG progress to generalized myasthenia gravis (gMG), a more serious form of MG. gMG is a rare chronic autoimmune disease characterized by severe, unpredictable, potentially life-threatening muscle weakness throughout the body.1 About half of those with gMG are considered uncontrolled, experiencing unpredictable attacks, leading to struggles with activities of daily living such as walking, eating, and breathing. These attacks vary from person to person and can become worse with stress, hot or cold weather, infections, or medications. While gMG may often be called MG, it is important to know that patients with gMG will experience more widespread and severe symptoms than those with ocular MG.2
Antibodies are proteins produced by the immune system that normally protect from infection or harmful substances in the body. gMG occurs when antibodies attack where the nerves and muscles meet in the body causing muscle fatigue and weakness. Patients with gMG primarily produce two types of antibodies: 8 out of 10 people produce anti-AChR (acetylcholine receptor) antibodies whereas 1.5 out of 10 people produce anti-MuSK (muscle-specific tyrosine kinase) antibodies. Anti-AChR antibodies destroy the receptors for acetylcholine (ACh), which are needed for normal muscle movement. Anti-MuSK antibodies also cause muscle weakness by affecting the messaging pathway in the nerves.2