Differential Diagnosis in Tyrosinemia	
			
Tyrosinemia type I 	Deficiency of fumarylacetoacetate hydrolase	Family history
Neurologic crises
Signs liver dysfunction
Succinylacetone in blood or urine	
Transient tyrosinemia of the newborn	Immaturity of parahydroxyphenylpyruate dehydrogenase	Frequently in infants
Disappears spontaneously
Administration of vitamin C and dietary restriction	
Hawkinsinuria	Abnormality of parahydroxyphenylpyruvate dehydrogenase	Acidosis and hypertyrosinemia
Organic compound (hawkinsis) in the urine	
Tyrosinemia type II 	Deficiency of tyrosine aminotransferase	Hyperkeratosis of the palm and soleil
Corneal thickening
Hepatic and renal function remain intact	
Hepatocellular dysfunction	Deficiency of maleylacetoacetate isomerase		
Alcaptonuria	Deficiency homogentisate oxidase	Arthritis in middle age
Darkening of urine when exposed to air
Excessive urinary excretion of homogentisic acid 	
Phenylketonuria	Deficiency phenylalanine hydroxylase	High blood level of phenylalanine
Phenynalanine restriction prevent mental retardation