Which statement about myasthenia gravis is true?

• A. It primarily affects sensory neurons
• B. It is a chronic autoimmune disease that affects the neuromuscular junction and produces weakness
• C. It is not autoimmune
• D. It causes hyperreflexia

Answer: (B)

Myasthenia gravis is an autoimmune disorder in which antibodies target components of the neuromuscular junction, most commonly the acetylcholine receptor. This disrupts transmission from nerve to muscle, so voluntary muscles become progressively weaker with use and improve with rest. Because the problem is at the motor end plate, sensory pathways are not the primary issue, which is why this condition does not primarily affect sensory neurons. It is indeed autoimmune, aligning with the description of a chronic autoimmune disease that affects the neuromuscular junction and causes weakness. Hyperreflexia does not fit MG; reflexes are usually normal or reduced due to muscle weakness, not heightened as seen with upper motor neuron disorders.