Lecture: Urine Screening for Metabolic Disorders Flashcards
Failure to inherit a gene to produce enzyme phenylalanine hydroxylase
Phenylketonuria
The accumulation of excess tyrosine in the plasma (tyrosinemia) producing urinary overflow may be due to several causes and is poorly categorized
Tyrosyluria
Increased urinary melanin darkens the urine. The darkening appears after the urine is exposed to air.
Melanuria
Urine from patients with this condition darkened after becoming alkaline from standing at room temperature
Alkaptonuria
Failure to inherit the gene to produce enzyme homogentisic acid oxidase
Alkaptonuria
The branched-chain amino acids differ from other amino acids by having a methyl group that branches from the main aliphatic carbon chain. True or False?
True
Caused by an inborn error of metabolism (IEM), inherited as an autosomal recessive trait
Maple Syrup Urine Disorder (MSUD)
Amino acids involved in MSUD
Leucine
Isoleucine
Valine
Screening test used for MSUD
2,4-dinitrophenylhydrazine (DNPH) urine screening test
Positive reaction on DNPH urine screening test produces?
Yellow turbidity/precipitate
Symptoms of this disorder include early severe illness, often with vomiting accompanied by metabolic acidosis, hypoglycemia, ketonuria, and increased serum ammonia
Organic Acidemias
Three most frequently encountered organic acidemia are?
Isovaleric Acidemia
Propionic Acidemia
Methylmalonic Acidemia
Indican excreted in the urine is colorless until oxidized to the dye indigo blue by exposure to air
Indicanuria
Term of “blue diaper syndrome” due to blue staining of infant’s diaper when affected
Hartnup disease
These tests/reactions is used to detect what disorder?
Guthrie test (bacterial inhibition)
FeCl3 tube: blue-green
Phenylketonuria
These tests/reactions is used to detect what disorder?
Nitroso-naphthol: orange red FeCl3 tube test: transient green
Tyrosyluria
These tests/reactions is used to detect what disorder?
Sodium nitroprusside: red Ehrlich’s: red
FeCl3: gray or black precipitate
Melanuria
These tests/reactions is used to detect what disorder?
Benedict’s/Clinitest: yellow precipitate FeCl3: transient blue
Alkaptonuria
These tests/reactions is used to detect what disorder?
FeCl3: violet with chloroform
Obermayer’s Test
Indicanuria
Characterized by increased 5-Hydroxyindoleacetic acid (5-HIAA)
Argentaffinoma
Serotonin-rich diet
Banana
Tomatoes
Pineapple
Serotonin is produced from phenylalanine by the argentaffin cells in the intestine and is carried through the body primarily by the platelets. True or False?
False. Serotonin is produced by tryptophan
Presence of these that involves argentaffin cells development, excess amount of serotonin is produced
Carcinoid tumors
Defect in renal tubular transport of cystine, ornithine, lysine and arginine
Cystinuria
Inborn error of metabolism. Cystine deposits in many areas of the body.
Cystinosis
Defects in the metabolism of the amino acid methionine produce an increase in homocystine throughout the body
Homocystinuria
A positive reaction in the silver-nitroprusside test confirms the presence of homocystinuria. True or False?
True
The decreased homocystine can result in failure to thrive, cataracts, mental retardation, thromboembolic problems, and death. True or False?
False. Increased homocystine produces these results
Fresh urine should be used when testing for homocystine. True or False?
True
The basic pathway for heme synthesis have three primary porphyrins which are?
Uroporphyrin
Coproporphyrin
Protoporphyrin
What are the porphyrin precursors?
α -aminolevulinic acid (ALA)
porphobilinogen
Possible presence of porphyrinuria is the observation of a violet wine color to the urine after exposure to air. True or False?
False. Red or port-wine color of urine is observed
The two screening tests for porphyrinuria are?
Ehrlich reaction
Fluorescence under UV light in the 550- to 600-nm range
What type of porphyria is being described?
Increased ALA porphobilinogen
Tested by Urine/Ehrlich reaction
Acute intermittent porphyria
What type of porphyria is being described?
Increased uroporphyrin
Tested by urine fluorescence
Porphyria cutanea tarda
What type of porphyria is being described?
Increased uroporphyrin and coproporphyrin
Tested by urine/feces fluorescence
Congenital erythropoietic porphyria
What type of porphyria is being described?
Increased porphyrin
Tested by bile or feces fluorescence
Variegate porphyria
What type of porphyria is being described?
Increased protoporphyrin
Tested by blood FEP and bile/feces fluorescence
Erythropoietic porphyria
What type of porphyria is being described?
Increased ALA and protopophyrin
Tested by acetoacetic acid + urine/Ehrlich reaction or Blood FEP
Lead poisoning
The incompletely metabolized polysaccharide products most frequently found in the urine?
Dermatan sulfate
Keratan sulfate
Heparan sulfate
Types of mucopolysaccharidoses
Hurler Syndrome
Hunter Syndrome
Sanflippo Syndrome
Mucopolysaccharide screening tests that produces white turbidity in positive reaction
Acid-Albumin
Cetyltrimethylammonium bromium (CTAB)
Azure A in acetic acid/MPS paper: blue spot is produced in what test for mucopolysaccharide?
Metachromatic staining
Inherited as a sex-linked recessive result in massive excretion of urinary uric acid crystals
Lesch-Nyhan Disease
Failure to inherit the gene to produce this enzyme will result to the accumulation of uric acid throughout the body
Hypoxanthine-guanine phosphoribosyltransferase
The presence of increased urinary sugar is known as?
Melituria
The finding of a positive copper reduction test result combined with a negative reagent strip glucose oxidase test result is strongly suggestive of a disorder of carbohydrate metabolism. True or False?
True
Caused by a deficiency in any of three enzymes, galactose-1-phosphate uridyl transferase (GALT), galactokinase, and UDP-galactose-4-epimerase
Galactosuria
What dysfunctional defect is described in these disorders?
Phenylketonuria
Tyrosinemia
Alkaptonuria
MSUD
Organic Acidemia
Cystinosis
Porphyria
Mucopolysaccharidoses
Galactosemia
Lesch-Nyhan Disease
Overflow Inherited
What dysfunctional defect is described in these disorders?
Infantile tyrosinemia
Melanuria
Indicanuria
5-HIAA
Porphyria
Metabolic
What dysfunctional defect is described in these disorders?
Hartnup Disease
Cystinuria
Renal
