Tyrosine is derived from ingested proteins or is synthesized endogenously from phenylalanine. It is used for protein synthesis and is a precursor of dopamine, norepinephrine, epinephrine, melanin, and thyroxine. Tyrosinemia type I or Hereditary tyrosinemia or Hepatorenal tyrosinemia Caused by a deficiency of the enzyme fumarylacetoacetate hydrolase. Hepatic disease, peripheral neuropathy and renal involvement are hallmark of disease. The presence of elevated levels of succinylacetone in serum and urine is diagnostic