Who gets myasthenia gravis?

Myasthenia gravis 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.

In neonatal myasthenia, the fetus may acquire immune proteins (antibodies) from a mother affected with myasthenia gravis. Generally, cases of neonatal myasthenia gravis are temporary and the child's symptoms usually disappear within 2-3 months after birth. Other children develop myasthenia gravis indistinguishable from adults. Myasthenia gravis in juveniles is uncommon.

Myasthenia gravis is not directly inherited nor is it contagious. Occasionally, the disease may occur in more than one member of the same family.

Rarely, children may show signs of congenital myasthenia or congenital myasthenic syndrome. These are not autoimmune disorders, but are caused by defective genes that produce abnormal proteins instead of those which normally would produce acetylcholine, acetylcholinesterase (the enzyme that breaks down acetylcholine), or the acetylcholine receptor and other proteins present along the muscle membrane.