Tyrosine is the precursor of some neurotransmitters (for example, dopamine, norepinephrine, adrenaline), hormones (eg, thyroxine), and melanin; deficiency of enzymes involved in their metabolism, leads to a number of syndromes. Type I tyrosineemia - this disease is inherited by an autosomal recessive type, caused by a deficiency of fumaryl-acetoacetate hydroxylase, an enzyme involved in the metabolism of tyrosine.