This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
NARP syndrome is a type of: 
Select and explain. 
A. Mitochondrial function disorder, B. Glycogen storage disorder, C. Lysosomal storage disorder, D. Lipid storage disorder
A: Mitochondrial function disorder
Answer: A: Mitochondrial function disorder 
Explanation: NARP ( Neuropathy, Ataxia, Retinitis pigmentosa ) disease is associated with mitochondrial DNA point mutation at base pair 8993 causinga substitution of thymidine by guanine in the gene coding for the subunit 6 of ATP synthase. Ref: Clinical Pediatric Neurology By Ronald B. David, Page 304.