Occurrence of Myasthenia Gravis

Estimates of the number of people affected by MG vary, ranging from five to 14 people per 100,000.

MG occurs in all ethnic groups and both genders. It most commonly affects young adult women (under 40) and older men (over 60), but it can occur at any age. Children sometimes develop MG.

MG is not directly inherited nor is it contagious. Sometimes the disease may occur in more than one member of the same family. If a woman with MG becomes pregnant, sometimes the baby acquires antibodies from the mother and has MG symptoms for a few weeks or months after birth. This is called neonatal myasthenia, and the symptoms can be treated.

In rare cases, myasthenia is caused by a defective gene and appears in infants born to non-myasthenic mothers. This type is called congenital myasthenia.