A deficiency of the enzyme in humans can result in what is known as type II tyrosinemia, wherein there is an abundance of tyrosine as a result of tyrosine failing to undergo an aminotransferase reaction to form 4-hydroxyphenylpyruvate.
A scarcity of the enzyme in humans can lead to what is referred to as type II tyrosinemia, where there is an overabundance of tyrosine due to tyrosine failing to undergo a transamination reaction to form 4-hydroxyphenylpyruvate.