Urinalysis and Body Fluids 6th Edition by Majorie DiLorenzo, Susan Strasinger

Exercise 2

The least serious form of tyrosylemia is:

A. Immature liver function

B. Type 1

C. Type 2

D. Type 3

Step 1 of 2

Tyrosinemia: (tyrosyluria or tyrosylemia)

• Excess accumulation of tyrosine in plasma is called tyrosinemia

• Deficient of enzyme to complete metabolism of tyrosine causes transitory tyrosinemia

• The disorder is associated with Phenylalanine-tyrosine pathway

There are three types of tyrosinemia:

• Type 1 tyrosinemia is caused by lack of fumarylacetoacetate hydrolase enzyme

• Type 2 tyrosinemia occurs due to shortage of tyrosine aminotransferase enzyme

• Type 3 tyrosinemia is caused by lack of p-hydroxyphenylpyruvic acid dioxygenase

Immature liver function:

• Under developed liver function produces transitory tyrosinemia in infants

• It requires necessary enzyme for completion tyrosine metabolism

• The condition produces leucine, and tyrosine crystals in urine sediment

• It is not a much serious form

Therefore, “immature liver function” causes transitory tyrosinemia in infants. It is the least serious form. Hence, the correct answer is option.