Destruction of the myelin sheath of axons caused by the presence of antibody is characteristic of which disease?

• A. MG
• B. Graves disease
• C. Goodpasture's syndrome
• D. MS

Answer: (D)

The key idea is autoimmune destruction of myelin in the central nervous system, which interrupts nerve signaling. In multiple sclerosis, immune cells and antibodies target the myelin sheaths around CNS axons, leading to patchy demyelination and damage to oligodendrocytes. This slows or blocks conduction and causes the varied neurological symptoms seen in MS, depending on where lesions form.

Other conditions listed involve different targets and systems. Myasthenia gravis is a problem at the neuromuscular junction caused by antibodies against acetylcholine receptors, leading to muscle weakness but not CNS demyelination. Graves disease results from antibodies stimulating the TSH receptor, causing hyperthyroidism, not demyelination. Goodpasture’s syndrome features antibodies against basement membranes in kidneys and lungs, leading to renal and pulmonary issues, with no involvement of myelin.

So, the description of myelin destruction by an autoimmune process points to multiple sclerosis.