Chapter 33: Geoepidemiology of myasthenia gravis

Myasthenia gravis (MG) is an autoimmune disease that affects the post-synaptic area of the neuromuscular junction. Its hallmark is weakness that worsens with activity. MG incidence is rising in the recent decades, mostly the late onset subtype, which is considered to be due to the aging population or unknown environmental factors. The disease has several subtypes which defer slightly in the clinical characteristics, immunological markers, population distribution and the suitable treatments. The autoimmune nature of the disease is manifested by a decrease in the number of acetylcholine receptors in the muscle receptors which makes the endplate potential to be lower than the threshold needed to activate muscle fiber action potential. In our review we try to find the environmental influence on the disease. (C) 2009 Elsevier B.V. All rights reserved.