Richard Hanha syndrome is caused by defective metabolism of:
High-Yield Explanation
Following transamination, the carbon skeleton of tyrosine is degraded to fumarate and acetoacetate. Metabolic diseases of tyrosine catabolism include tyrosinosis, Richner-Hanha syndrome, neonatal tyrosinemia, and alkaptonuria. Ref: Harper 28th edition, chapter 29.