This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Enzymes, Subject name: Biochemistry
Refsum's disease is due to accumulation of 
Select and explain. 
A. C26-C38 polyenoic acids, B. C6-C10 o-dicarboxylic acids, C. Palmitic acid, D. Phytanic acid
D: Phytanic acid
Answer: D: Phytanic acid 
Explanation: Refsum disease is a rare neurologic disorder due to a metabolic defect that results in the accumulation of phytanic acid, which is found in dairy productsand ruminant fat and meat. Phytanic acid is thought to have pathological effects on membrane function, protein prenylation, and gene expression.Ref: Harper&;s Biochemistry; 30th edition; Chapter 22; Oxidation of Fatty Acids: Ketogenesis