Final Exam Flashcards
1
Q
NAcGlu Synth Def
A
- Problem
- defect in enz (NAGS) that makes N-acetylglutamate
- from Glu + Acetyl CoA
- excess blood ammonia building up
- carbamoyl phosphate synthetase I not activated
- inhibit first step of urea cycle
- defect in enz (NAGS) that makes N-acetylglutamate
- Treat
- Carbamoyl glutamate is an analog that activates CPS1
- stimulates urea cycle + removal of ammonia
2
Q
Carbamoyl phosphate synthetase I def
A
- Problem
- defect in Carbamoyl phosphate synthetase I
- Results
- low urea cycle intermediates
- high NH3
3
Q
Ornithine transcarbamoylase def
OTC most common UCD
X linked
A
- Problem
- defect in OTC whic forms citrulline
- from carbamoyl phosphate and ornithine
- defect in OTC whic forms citrulline
- Results
- high ammonia levels
- Build up of glutamate and alanine
- High levels of orotate in urine
- Treat
- citrulline
4
Q
Argininosuccinate synthetase def
Citrullinemia type I
A
- Problem
- defect in ASS, enzyme that synthesizes argininosuccinate
- from citrulline and aspartate
- defect in ASS, enzyme that synthesizes argininosuccinate
- Result
- very high citrulline + NH3 levels
- Treat
- arginine
5
Q
Argininosuccinate lyase def
A
- Problem
- defect in ASL, converts argininosuccinate into arginine + fumarate
- Result
- high levels of argininosuccinate + NH3
- Treat
- arginine
6
Q
Arginase Def
A
- Problem
- defect in arginase
- hydrolizes arginine into urea + ornithine
- defect in arginase
- Result
- high levels of arginine
- mild levels of NH3
- progressive neurologic symptoms
- seizures
- stunted growth
7
Q
Phenylketonuria
A
- Problem
- defect in phenylalanine hydroxylase
- restricts phenylalanine to tyrosine conversion
- defect in phenylalanine hydroxylase
- Result
- drastic IQ reduction
- seizures
- mental + behavioral disorders
- urine has a sweet mouse-like odor
- small head + low birth weight
- Treat
- low phenylalanine diet
8
Q
Tyrosinemias
A
- Problem
- defect in fumarylacetoacetate hydrolase
- Result
- high succinyl-acetone in urine
- cabbage-like odor
- liver + kidney failure
- failure to thrive
- Treat
- dietary restriction of Phe + Tyr
- nitisinone
- build up of non-toxic intermediate instead
9
Q
Alkaptonuria
A
- Problem
- defect in homogentisate 1,2-dioxygenase
- Results
- high homogentisate
- black urine disease
- tar substance in joints
- Treat
10
Q
Cystinosis
AA Metabolism
A
- Problem
- defect in transport of cystine out of lysosome
- Results
- formation of cystine crystals w.i. lysosome
11
Q
Cystinuria
A
- Problem
- can not properly reabsorb cystine into their bloodstream
- concentrates in urine
- Disorder of the proximal tubule’s reabsorption of filtered cysteine and dibasic AA’s (ornithine, arginine, & lysine)
- Result
- high cysteine in urine
- formation of cystine stones in the kidneys, ureter, and bladder
- Treat
- hydration + diet mods (decrease methionine intake)
- chelation agents
12
Q
Homocystinuria
A
- Problem
- defect in cystathionine synthase
- conversion of methionine - > - > - > cysteine
- defect in cystathionine synthase
- Result
- high homocysteine in urine
- highmethionine + metabolites
- intellectual disabiltiy
- osteoporosis
- discoloration of lens
13
Q
Hartnup disease
A
- Problem
- inability to absorb/transport neutral AA such as tryptophan
- Result
- low blood tryptophan levels
- increased urine excretion of tryptophan
- skin eruptions
- cerebellar ataxia
- mental retardation
- Treat
- oral hydration
14
Q
Maple syrup urine disease
A
- Problem
- defect in branched chain a-keto acid dehydrogenase
- BCAA key role in Glu supply
- major neuro affects
- BCAA key role in Glu supply
- defect in branched chain a-keto acid dehydrogenase
- Results
- maple syrup urine odor
- high leucine levels (toxic)
- mental and physical retardation
- Treat
- low valine, isoleucine, + leucine diet
15
Q
MCAD
A
- Problem
- defect in medium-chain acyl-CoA dehydrogenase
- Results
-
hypoketotic
- no fat break down therefore no ketones
-
hypoglycemic
- glycolysis only
- build up of acetyl-CoA
- activates pyruvate carboxylase
- high levels of MCFA, dicarboxylic acids, acylcarnitines, + acylglycines
- dicarboxylic acids product of omega oxidation
-
hypoketotic
16
Q
Primary carnitine deficiency
A
- Problem
- defect in a transporter OCTN2
- impaired transport of LCFA into cells for B-Ox
- Results
- low free carnitine, acylcarnitine, + ketone bodies
- high free fatty acids
- hypoketotic, hypoglycemic
- Treat
- carnitine
- low fat diet
- frequent meals
17
Q
Zellweger Syndrome
A
- Problem
-
severe total loss of functional peroxisomes
- responsible for B-Ox of VLCFA + cholesterol synth
-
severe total loss of functional peroxisomes
- Results
- death w.i. 1st year
- high VLCFA in blood
- impaired brain development
- dysmorphic faces + progressive degeneration of brain, liver, + kidneys
18
Q
Refsum Disease
A
- Problem
- defect in degradation of BCFA
- partial breakdown of branched-chain fatty acids –> toxic intermediate
- defect in degradation of BCFA
- Results
- buildup of phytanic acid
- ataxia
- scaly skin + skin abnormalities
- difficulty hearing + eye problems
19
Q
X-linked adrenoleukodystrophy
A
- Problem
- nonfunctional transporter into peroxisome
- VLCFA can’t get into peroxisome
- Result
- hypomyelination in brain
- adrenocortical insufficiency