<prompt> Mousy odour urine is seen in:Maple syrup urinePhenylketonuriaIsovalericaciduriaCystinuria  <response>: Phenylketonuria is caused by deficiency of phenylalanine hydroxylase or dihydrobiopterin BH2 reductase, which regenerates BH4 from BH2. It presents with mousy musty odour in urine and emerald green colour in FeC13 test. The aim of first line therapy is to limit the substrate i.e. phenylalanine for deficient enzyme 