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

Exercise 5

An overflow disorder of the phenylalanine-tyrosine pathway that would produce a positive reaction with the reagent

strip test for ketones is:

A. Alkaptonuria

B. Melanuria

C. MSUD

D. Tyrosyluria

Step 1 of 2

Overflow disorders:

Over flow disorders are caused due to disturbance in metabolic pathway, which causes increased nonmetabolized substances in plasma.

• The disorder included in over flow type are,

o Maple syrup urine disease

o Cystinosis

o Porphyria

o Galactosemia

o Alkaptonuria

o Phenylketonuria

o Organic acidemias

o Lesch-Nyhan disease

o Mucopolysaccharidoses

o Tyrosinemia

o Phenylketonuria

Maple syrup urine disease (MSUD):

• It is caused by inborn error of metabolism, inherited as autosomal recessive characteristic

• Failure to inherit the gene, which produces necessary enzyme for oxidative decarboxylation of keto acid will result in accumulation of keto acid in urine, and blood

• Reagent strip test for ketone produces positive reaction for MSUD disorder

Therefore, “MSUD”, an over flow disorder of phenylalanine-tyrosine pathway gives positive reaction in ketone reagent strip test. Hence, the correct answer is option.