Which of the following conditions may present with diplopia and ptosis?

Myasthenia gravis is a neuromuscular disorder characterized by weakness and rapid fatigue of voluntary muscles. It is caused by an autoimmune response that affects the communication between nerves and muscles, mainly by blocking acetylcholine receptors at the neuromuscular junction. Diplopia, or double vision, and ptosis, which is drooping of one or both eyelids, are classic symptoms of myasthenia gravis. These symptoms occur due to the weakness of the ocular muscles, which can lead to misalignment of the eyes and difficulties in maintaining eyelid elevation.

Myasthenia gravis typically presents with fluctuating muscle weakness, and the ocular muscles are often among the first to be affected. This can lead to both diplopia and ptosis in many patients. Identifying these symptoms is critical for diagnosis and management of the condition, as they indicate the involvement of the ocular muscles and suggest that further testing (such as antibody testing or edrophonium testing) may be necessary to confirm the diagnosis. Treatment options like anticholinesterase inhibitors or immunosuppressants can effectively improve muscle strength and alleviate symptoms.

The other conditions listed do not commonly present with both diplopia and ptosis. For instance, Parkinson's disease primarily