MS differs from Parkinson's disease in that...

• A. The primary problem: Loss of dopamine-producing neurons
• B. It is caused by genetic neurodegeneration in basal ganglia
• C. It is primarily due to tau tangles and amyloid plaques
• D. It is primarily a demyelinating disorder, not a disorder of neuron death.

Answer: (D)

The main idea is that the two diseases differ in what goes wrong in the brain. Multiple sclerosis is driven by autoimmune loss of myelin in the CNS, so the defining issue is demyelination that disrupts nerve conduction across various pathways. Parkinson's disease, on the other hand, centers on the progressive death of dopamine-producing neurons in the substantia nigra, with motor symptoms arising from this neuron loss in the nigrostriatal circuit. Tau tangles and amyloid plaques point more to Alzheimer's disease, not MS. MS is not primarily a basal ganglia–centered genetic neurodegenerative process. So describing MS as primarily a demyelinating disorder, not a neuron-death disorder, best captures the difference.