MIDTERM - METABOLIC DISORDERS Flashcards
Disruption of enzyme function can be
caused by failure to inherit the gene to produce a particular
enzyme, referred to as an ___.
inborn error of metabolism (IEM),
___is capable of screening the infant blood
sample for specific substances associated with particular
IEMs
MS/MS - tandem mass spectrophotometry
The most well known of the aminoacidurias,
Phenylketonuria
PKU is estimated
to occur in ____ of every 10,000 to 20,000 births
1
if undetected, results in severe mental retardation.
Phenylketonuria
. 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
Phenylketonuria
PKU/ phenylketonuria is caused by failure to inherit the gene to produce the
enzyme ___.
phenylalanine hydroxylase
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
ferric chloride
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
blue-green
The accumulation of excess tyrosine in the plasma is called
tyrosinemia
tyrosine metabolism may result from _- or __-
either inherited or metabolic defects.
because two reactions are directly involved
in the metabolism of tyrosine, the urine may contain excess tyrosine or its degradation products,
__- and ___.
p-hydroxyphenylpyruvic
acid and p-hydroxyphenyllactic acid
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
transitory tyrosinemia
type 1 tyrosenimia
is caused by the deficiency
of the enzyme __
fumarylacetoacetate hydrolase (FAH)
type of tyrosinemia that produces a generalized renal tubular disorder and progressive
liver failure in infants soon after birth. T
type 1 tyrosinemia
___tyrosinemia is
caused by lack of the enzyme tyrosine aminotransferase.
Type 2
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
Type 2
Type 3 tyrosinemia is caused by lack of
the enzyme ___
p-hydroxyphenylpyruvic acid dioxygenase
This type of tyrosinemia can result in mental retardation if dietary restrictions of phenylalanine and tyrosine are not implemented.
type 3
second metabolic pathway also exists for
tyrosine. This pathway is responsible for the production of ___
melanin, thyroxine, epinephrine, protein, and tyrosine sulfate.
Deficient production of melanin
results in ___.
albinism
what are the normal byproducts of tyrosine on its secondary metabolic pathway?
melanin, thyroxine, epinephrine, protein, and tyrosine sulfate.
Increased urinary ___ darkens the urine. The darkening appears after the urine is exposed to air.
melanin
Elevated urinary
melanin is a serious finding that indicates proliferation of the
normal melanin-producing cells called
melanocytes
Elevated urinary
melanin is a serious finding that indicates proliferation of the
normal melanin-producing cells (melanocytes), producing a
malignant __.
melanoma
The name ___
was derived from the observation that urine from patients with
this condition darkened after becoming alkaline from standing
at room temperature.
alkaptonuria
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
Alkaptonuria
alkaptonuria starts when the patient failed to inherit the gene to produce what enzyme?
homogentisic acid oxidase
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
Alkaptonuria
A high percentage of persons with alkaptonuria develop what other organ disorder?
liver and cardiac disorders.
homogentisic acid accumulates and deposited in the cartilage can cause ___
– disease under alkaptonuria
arthritis
The amino acids involved arfor maple syrup disease are
leucine, isoleucine, and valine.
maple syrup disease
\
The metabolic pathway for transamination of the three amino acids in the
liver to the keto acids (____).
alpha - ketoisovaleric,
alpha -ketoisocaproic,
and
alpha-keto-beta-methylvaleric
___ may be suspected when urine specimens, and sometimes even the patient, possess a characteristic
odor of “sweaty feet
Isovaleric acidemia
This odor is “sweaty feet”caused by the accumulation
of ___ due to a deficiency of enzyme ___ in the leucine pathway
isovalerylglycine; isovaleryl coenzyme A
The presence of isovaleric, propionic, and methylmalonic
acidemias can be detected by newborn screening programs
using ___.
MS/MS - tandem mass spectrophotometry