URINE METABOLIC DISORDERS (Phenylalanine-Tyrosine disorders)

Question 1

What type of overflow condition results in increased amino acids in blood and urine?

Answer 1

PKU, MSUD, Cystinosis

Question 2

What is the renal type aminoaciduria with normal amino acids in blood and increased amino acids in urine?

Answer 2

Cystinuria, Fanconi’s syndrome

Question 3

What disorders are categorized as phenylalanine-tyrosine disorders?

Answer 3

Phenylketonuria, Tyrosyluria/Tyrosenemia, Alkaptonuria, Melanuria

Question 4

What gene is absent in Phenylketonuria?

Answer 4

Phenylalanine hydroxylase

Question 5

What causes other forms of phenylketonuria?

Answer 5

Tetrahydrobiopterin deficiency

Question 6

What is the odor associated with phenylketonuria?

Answer 6

Mousy urine, sweat, breath odor

Question 7

What condition may phenylketonuria lead to?

Answer 7

Mental retardation

Question 8

What is the positive result for the FeCl3 tube test for phenylketonuria?

Answer 8

Blue-green color

Question 9

What is the positive result for the Phenistix strip test for phenylketonuria?

Answer 9

Gray to gray-green color

Question 10

What does a positive Guthrie bacterial inhibition test show?

Answer 10

Growth in the media

Question 11

Which counteracts the action of B2-thienylalanine in the Guthrie bacterial inhibition test?

Answer 11

Phenylalanine

Question 12

What is the confirmatory test for Phenylketonuria?

Answer 12

Ion exchange HPLC

Question 13

What is absent in Type 1 tyrosyluria?

Answer 13

Fumarylacetoacetate hydrolase (FAH)

Question 14

What is absent in Type 2 tyrosyluria?

Answer 14

Tyrosine aminotransferase

Question 15

What is absent in Type 3 tyrosyluria?

Answer 15

p-hydroxyphenylpyruvic acid dioxygenase

Question 16

In which condition may tyrosyluria/tyrosinemia also be seen?

Answer 16

Severe liver disease

Question 17

What is the urine odor in tyrosinemia?

Answer 17

Rancid butter

Question 18

What is the positive result for the FeCl3 screening test for tyrosinemia?

Answer 18

Transient green

Question 19

What is the positive result for the Nitroso-napthol screening test for tyrosinemia?

Answer 19

Orange-red

Question 20

What is the confirmatory test for tyrosinemia?

Answer 20

Chromatography, quantitative serum assay of tyrosine

Question 21

What testing method is used for error of metabolism?

Answer 21

Tandem mass spectrophotometry (MS/MS)

Question 22

What enzyme is related to Tyrosinemia type 1b?

Answer 22

Maleylacetoacetic acid isomerase

Question 23

What enzyme is related to Tyrosinemia type 1a?

Answer 23

Fumarylacetoacetoacetic acid hydrolase

Question 24

What gene is absent in Alkaptonuria?

Answer 24

Homogentisic acid oxidase

Question 25

When does urine darken in Alkaptonuria?

Answer 25

After standing at room temperature (alkaline)

Question 26

What color does Alkaptonuria stain cloth diapers?

Answer 26

Brown or black

Question 27

What color do disposable plastic diapers stain in Alkaptonuria?

Answer 27

Reddish

Question 28

What pigmentation does homogentisic acid cause in connective tissues and ears in Alkaptonuria?

Answer 28

Black pigment (onchronosis)

Question 29

What is the treatment for Alkaptonuria?

Answer 29

Vitamin C

Question 30

What is the accumulation of Homogentisic Acid Oxidase in connective tissue called?

Answer 30

Onchrosis

Question 31

What are the positive results for the FeCl3, Clintest, and Silver nitrate tests for Alkaptonuria?

Answer 31

FeCl3 - transient blue, Clintest - yellow ppt, Silver nitrate - black color

Question 32

What is the confirmatory test for Alkaptonuria?

Answer 32

Paper/Thin layer chromatography Capillary electrophoresis GC-MS

Question 33

What condition causes melanuria?

Answer 33

Melanoma

Question 34

What substance does melanoma secrete to oxidize melanogen to melanin?

Answer 34

5,6-dihydroxyindole

Question 35

When does urine darken in melanuria?

Answer 35

Upon oxidation (air exposure)

Question 36

What condition can melanuria lead to due to deficient melanin production?

Answer 36

Albinism

Question 37

What are the positive results for the screening tests for melanuria?

Answer 37

FeCl3 - gray/black ppt Sodium nitroprusside - red color Ehrlich test - red color