This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S., Subject name: Medicine
Oochronosis occurs in: (Repeat) 
Select and explain. 
A. Alkaptonuria, B. Isovaleric aciduria, C. Phenyl ketonuria, D. Tyrosinemia
A: Alkaptonuria
Answer: A: Alkaptonuria 
Explanation: Ans: A (Alkaptonuria) Ref: Harrison's Principles of Internal Medicine, 18th ed.Explanation:AlkaptonuriaAutosomal RecessiveDue to deficiency of homogentisic acid oxidaseClinical featuresOochronosisArthritisCardiac valve involvementCoronary artery calcification Pigmented heart valves, sclera, joint, skin & renal calculiUrine darkens on standingNitisinone used to reduce urinary excretion of homogentisic acid