Monarch Disease Ontology term MONDO_0018324 (adult-onset myasthenia gravis) can be described as follows. Acquired myasthenia gravis (MG) is an autoimmune disorder of the neuromuscular junction characterized by fatigable muscle weakness with frequent ocular signs and/or generalized muscle weakness, and occasionally associated with thymoma. Also known as: adult-onset acquired myasthenia, adult-onset autoimmune myasthenia gravis.