MIDTERM - METABOLIC DISORDERS

Question 1

Disruption of enzyme function can be
caused by failure to inherit the gene to produce a particular
enzyme, referred to as an ___.

Answer 1

inborn error of metabolism (IEM),

Question 2

___is capable of screening the infant blood
sample for specific substances associated with particular
IEMs

Answer 2

MS/MS - tandem mass spectrophotometry

Question 3

The most well known of the aminoacidurias,

Answer 3

Phenylketonuria

Question 4

PKU is estimated
to occur in ____ of every 10,000 to 20,000 births

Answer 4

1

Question 5

if undetected, results in severe mental retardation.

Answer 5

Phenylketonuria

Question 6

. It was first identified
in Norway by Ivan Følling in 1934, when a mother with other
mentally retarded children reported a peculiar mousy odor to
her child’s urine

Answer 6

Phenylketonuria

Question 7

PKU/ phenylketonuria is caused by failure to inherit the gene to produce the
enzyme ___.

Answer 7

phenylalanine hydroxylase

Question 8

Urine testing using ___ may be used as a follow up test to ensure proper dietary control in previously diagnosed
cases and as a means of monitoring the dietary intake of pregnant women known to lack phenylalanine hydroxylase

Answer 8

ferric chloride

Question 9

Urine tests for phenylpyruvic acid are based on the ferric chloride reaction performed by tube test. The addition of ferric chloride to urine containing phenylpyruvic acid produces a
permanent __ color

Answer 9

blue-green

Question 10

The accumulation of excess tyrosine in the plasma is called

Answer 10

tyrosinemia

Question 11

tyrosine metabolism may result from _- or __-

Answer 11

either inherited or metabolic defects.

Question 12

because two reactions are directly involved
in the metabolism of tyrosine, the urine may contain excess tyrosine or its degradation products,
__- and ___.

Answer 12

p-hydroxyphenylpyruvic
acid and p-hydroxyphenyllactic acid

Question 13

in tyrosyluria, Most frequently seen is a ___ in premature infants, which is caused by underdevelopment of the liver
function required to produce the enzymes necessary to complete the tyrosine metabolism

Answer 13

transitory tyrosinemia

Question 14

type 1 tyrosenimia
is caused by the deficiency
of the enzyme __

Answer 14

fumarylacetoacetate hydrolase (FAH)

Question 15

type of tyrosinemia that produces a generalized renal tubular disorder and progressive
liver failure in infants soon after birth. T

Answer 15

type 1 tyrosinemia

Question 16

___tyrosinemia is
caused by lack of the enzyme tyrosine aminotransferase.

Answer 16

Type 2

Question 17

a type of tyrosinemia which the Persons develop corneal erosion and lesions on the palms, fingers,
and soles of the feet believed to be caused by crystallization of
tyrosine in the cells

Answer 17

Type 2

Question 18

Type 3 tyrosinemia is caused by lack of
the enzyme ___

Answer 18

p-hydroxyphenylpyruvic acid dioxygenase

Question 19

This type of tyrosinemia can result in mental retardation if dietary restrictions of phenylalanine and tyrosine are not implemented.

Answer 19

type 3

Question 20

second metabolic pathway also exists for
tyrosine. This pathway is responsible for the production of ___

Answer 20

melanin, thyroxine, epinephrine, protein, and tyrosine sulfate.

Question 21

Deficient production of melanin
results in ___.

Answer 21

albinism

Question 22

what are the normal byproducts of tyrosine on its secondary metabolic pathway?

Answer 22

melanin, thyroxine, epinephrine, protein, and tyrosine sulfate.

Question 23

Increased urinary ___ darkens the urine. The darkening appears after the urine is exposed to air.

Answer 23

melanin

Question 24

Elevated urinary
melanin is a serious finding that indicates proliferation of the
normal melanin-producing cells called

Answer 24

melanocytes

Question 25

Elevated urinary melanin is a serious finding that indicates proliferation of the normal melanin-producing cells (melanocytes), producing a malignant __.

Answer 25

melanoma

Question 26

The name ___ was derived from the observation that urine from patients with this condition darkened after becoming alkaline from standing at room temperature.

Answer 26

alkaptonuria

Question 27

This metabolic defect is actually the third major defect in the phenylalanine-tyrosine pathway and occurs from failure to inherit the gene to produce the enzyme homogentisic acid oxidase

Answer 27

Alkaptonuria

Question 28

alkaptonuria starts when the patient failed to inherit the gene to produce what enzyme?

Answer 28

homogentisic acid oxidase

Question 29

This condition does not usually manifest itself clinically in early childhood, but observations of brown-stained or black-stained cloth diapers and reddish-stained disposable diapers have been reported

Answer 29

Alkaptonuria

Question 30

A high percentage of persons with alkaptonuria develop what other organ disorder?

Answer 30

liver and cardiac disorders.

Question 31

homogentisic acid accumulates and deposited in the cartilage can cause ___ -- disease under alkaptonuria

Answer 31

arthritis

Question 32

The amino acids involved arfor maple syrup disease are

Answer 32

leucine, isoleucine, and valine.

Question 33

maple syrup disease \ The metabolic pathway for transamination of the three amino acids in the liver to the keto acids (____).

Answer 33

alpha - ketoisovaleric, alpha -ketoisocaproic, and alpha-keto-beta-methylvaleric

Question 34

___ may be suspected when urine specimens, and sometimes even the patient, possess a characteristic odor of “sweaty feet

Answer 34

Isovaleric acidemia

Question 35

This odor is "sweaty feet"caused by the accumulation of ___ due to a deficiency of enzyme ___ in the leucine pathway

Answer 35

isovalerylglycine; isovaleryl coenzyme A

Question 36

The presence of isovaleric, propionic, and methylmalonic acidemias can be detected by newborn screening programs using ___.

Answer 36

MS/MS - tandem mass spectrophotometry

Question 37

other acidemia aside from the isovaleric

Answer 37

Propionic and methylmalonic acidemias

Question 38

Propionic and methylmalonic acidemias result from errors in the metabolic pathway converting isoleucine, valine, threonine, and methionine to ___

Answer 38

succinyl coenzyme A.

Question 39

___ is the immediate precursor to methylmalonic acid in this pathway.

Answer 39

Propionic acid

Question 40

The major concern of the urinalysis laboratory in the metabolism of TRYPTOPHAN is the increased urinary excretion of the metabolites ____ and ___

Answer 40

indican and 5-hydroxyindoleacetic acid (5-HIAA)

Question 41

Early diagnosis of Hartnup disease is sometimes made when a mother reports a blue staining of her infant’s diapers, referred to as the “___.”

Answer 41

blue diaper syndrome

Question 42

The inherited defect in Hartnup disease affects not only the intestinal reabsorption of tryptophan but also the renal tubular reabsorption of other amino acids, resulting in a generalized aminoaciduria (____).

Answer 42

Fanconi syndrome

Question 43

a second metabolic pathway of tryptophan is for the production of ___ used in the stimulation of smooth muscles.

Answer 43

serotonin

Question 44

Serotonin is produced from tryptophan by the __ in the intestine and is carried through the body primarily by the platelets.

Answer 44

argentaffin cells

Question 45

A noticeable odor of ___ may be present in the urine of people with cystine metabolism disorders.

Answer 45

sulfur

Question 46

____is marked by elevated amounts of the amino acid cystine in the urine.

Answer 46

cystinuria

Question 47

Regarded as a genuine IEM,

Answer 47

cystinosis

Question 48

The presence of increased urinary cystine is not due to a defect in the metabolism of cystine but, rather, to the ___

Answer 48

inability of the renal tubules to re-absorb cystine filtered by the glomerulus

Question 49

The disorder cystinuria has two modes of inheritance

Answer 49

One in which reabsorption of all four amino acids—cystine, lysine, arginine, and ornithine—is affected and the other is only cystine and lysine are not reabsorbed

Question 50

Reduction of cystine by sodium cyanide followed by the addition of nitroprusside produces a __ color in a specimen that contains excess cystine

Answer 50

red-purple

Question 51

Defects in the metabolism of the amino acid methionine produce an increase in ___ throughout the body.

Answer 51

homocystine

Question 52

The increased __ can result in failure to thrive, cataracts, mental retardation, thromboembolic problems, and death

Answer 52

homocystine

Question 53

an additional screening test for homocystinuria must be per formed by following a positive cyanide-nitroprusside test result with a __ test, in which only homocystine will react

Answer 53

silver-nitroprusside test

Question 54

function of silver nitrate to confirm the presence of homocystinuria

Answer 54

The use of silver nitrate in place of sodium cyanide reduces homocystine to its nitroprusside-reactive form but does not reduce cystine. C

Question 55

__ are the intermediate compounds in the production of heme

Answer 55

Porphyrins

Question 56

three primary porphyrins

Answer 56

uroporphyrin, coproporphyrin, and protoporphyrin

Question 57

porphyrin precursors

Answer 57

(a-aminolevulinic acid [ALA] and porphobilinogen)

Question 58

among the primary porphyrins, which one is not seen in urine?

Answer 58

protoporphyrin

Question 59

The Centers for Disease Control and Pre vention (CDC) recommends analysis of whole blood for the presence of __ as a screening test for lead poisoning.

Answer 59

free erythrocyte protoporphyrin (FEP)

Question 60

Disorders of porphyrin metabolism are collectively termed __.

Answer 60

porphyrias

Question 61

An indication of the possible presence of ___ is the observation of a red or port wine color to the urine after exposure to air.

Answer 61

porphyrinuria

Question 62

The port wine urine color is more prevalent in the ___, and staining of the teeth may also occur

Answer 62

erythropoietic porphyrias

Question 63

As seen with other inherited disorders, the presence of ___ is sometimes suspected from a red discoloration of an infant’s diaper

Answer 63

congenital porphyria

Question 64

The two screening tests for porphyrinuria use the __ and ___ under ultraviolet light in the 550- to 600-nm range.

Answer 64

Ehrlich reaction and fluorescence

Question 65

test for porphyrinuria The ___ can be used only for the detection of ALA and porphobilinogen.

Answer 65

Ehrlich reaction

Question 66

__ must be added to the specimen to convert the ALA to porphobilino gen prior to performing the Ehrlich test.

Answer 66

Acetyl acetone

Question 67

Testing for the presence of __is most useful when patients exhibit symptoms of an acute attack.

Answer 67

porphobilinogen

Question 68

Mucopolysaccharides is also called as

Answer 68

glycosaminoglycans

Question 69

undigested Mucopolysaccharides are frequently found in the urine in a form of

Answer 69

dermatan sulfate, keratan sulfate, and heparan sulfate with the appearance of a particular substance being determined by the specific metabolic error that was inherited

Question 70

There are many types of mucopolysaccharidoses, but the best known are

Answer 70

Hurler syndrome, Hunter syndrome, and Sanfilippo syndrome

Question 71

In both Hurler and Hunter syndromes, the skeletal structure is ___ and there is severe ___;

Answer 71

abnormal; mental retardation

Question 72

among the mucopolusaccharidoses which one is the only syndrome that has mental retardation is the only manifstation?

Answer 72

Sanfilippo syndrome

Question 73

mucopolysaccharides accumulate in the cornea of the eye.

Answer 73

hurler syndrome

Question 74

a mucopolysaccjaridoses that is inherited as sex-linked recessive and is rarely seen in females

Answer 74

Hunter syndrome

Question 75

___ and __ are the most promising treatments for mucopolysaccharidoses

Answer 75

Bone marrow transplants and gene replacement therapy

Question 76

A disorder of purine metabolism known as ___

Answer 76

Lesch-Nyhan disease

Question 77

a purine disorder that is inherited as a sex-linked recessive results in massive excretion of urinary uric acid crystals.

Answer 77

Lesch-Nyhan disease

Question 78

In Lesh Nyhan disease, Failure to inherit the gene to produce the enzyme _____ is responsible for the accumulation of uric acid throughout the body.

Answer 78

hypoxanthine guanine phosphoribosyltransferase

Question 79

Patients suffer from severe motor defects, mental retardation, a tendency toward self destruction, gout, and renal calculi.

Answer 79

Lesch-Nyhan disease

Question 80

first sign is often uric acid crystals resembling orange sand in diapers.

Answer 80

Lesch-Nyhan disease

Question 81

The presence of increased ____ is most frequently due to an inherited disorder

Answer 81

urinary sugar (melituria)

Question 82

The presence of increased urinary sugar (melituria) is most frequently due to an inherited disorder. In fact, ____ was one of Garrod’s original six IEMs.

Answer 82

pentosuria

Question 83

Of primary concern is the presence of ___, indicating the inability to properly metabolize galactose to glucose

Answer 83

galactosuria

Question 84

Galactosuria can be caused by a deficiency in any of three enzymes, ___, ___, and ___

Answer 84

galactose-1-phosphate uridyl transferase (GALT), galactokinase, and UDP-galactose-4-epimerase.

Question 85

Of these enzymes, it is ___ that causes the severe, possibly fatal symptoms associated with galactosemia

Answer 85

GALT deficiency (galactose-1-phosphate uridyl transferase )

Question 86

. a melituria that may be seen during pregnancy and lactation

Answer 86

Lactosuria

Question 87

a melituria associated with parenteral feeding

Answer 87

Fructosuria

Question 88

a melituria that is associated with ingestion of large amounts of fruit

Answer 88

pentosuria