Certified Neuroscience Registered Nurse (CNRN) Practice Exam

Which of the following conditions is characterized by a lack of an enzyme that breaks down very long-chain fatty acids?

1. Adrenoleukodystrophy (ALD)

2. Creutzfeldt-Jakob disease

3. Huntington's disease

4. Wernicke's encephalopathy

The correct answer is: Adrenoleukodystrophy (ALD)

The condition characterized by a lack of an enzyme that breaks down very long-chain fatty acids is Adrenoleukodystrophy (ALD). In ALD, there is a deficiency of the enzyme that is responsible for the oxidation of very long-chain fatty acids, leading to their accumulation in the body. This accumulation can cause significant damage to the myelin sheath of the brain and spinal cord, leading to various neurological symptoms. Understanding this mechanism is crucial, especially in neurology, as it highlights the importance of lipid metabolism in neurological health. The symptoms of ALD often include behavioral changes, cognitive decline, and physical disabilities, which stem from the progressive neurological damage caused by the buildup of these fatty acids. In contrast, Creutzfeldt-Jakob disease is a prion disease that affects the brain, resulting in rapidly progressive dementia and neurological decline, but it does not involve fatty acid metabolism. Huntington's disease is a genetic disorder characterized by the progressive degeneration of neurons, particularly in the basal ganglia, and is related to a mutation in the huntingtin gene, not fatty acid metabolism. Wernicke's encephalopathy results from thiamine (vitamin B1) deficiency, affecting brain function and causing symptoms related to memory and