Biochemistry - Nutrition and Metabolism 2 Flashcards by Ofir Gorelik

Hyperammonemia Treatment:

limit protein in the diet.
May be given to dec ammonia levels:

Lactulose to acidify GI tract and trap NH4 + for excretion.
Antibiotics (eg, rifaximin, neomycin) to kill ammoniagenic bacteria.
Benzoate, phenylacetate, or phenylbutyrate react with glycine or glutamine, forming products that are excreted renally.

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Hyperammonemia metabolic effects

NH3+ depletes glutamate in the CNS

inhibits the TCA cycle ( dec. a-ketoglutarate).

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Arginine used to synthesize:

Creatine
Urea
Nitric oxide
(creat ur No)

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Catecholamine synthesis/tyrosine catabolism

Phenylalanine - tyrosine - DOPA -Dopamine - Norepinephrine - Epinephrine

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Catecholamine synthesis/tyrosine catabolism:

Phenylalanine and tyrosine both use…

hydroxylase and BH4

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DOPA to Dopamine needs

dopa decarboxylase and B6

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Dopamine to Norepinephrine needs…

dopamine beta-hydroxylase and vit C

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Norepinephrine to Epinephrine needs…

Phenylethanolamine-N-methyltransferase and SAM

Induced by cortisol

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Norepinephrine and Epinephrine metabolized to and by…

Vaniltymandelic acid

COMT

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Dopamine metabolized to

Homovanillic acid

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Homocystinuria Caused by:

Cystathionine synthase deficiency
dec. affinity of cystathionine synthase for pyridoxal phosphate
Methionine synthase (homocysteine methyltransferase) deficiency
Methylenetetrahydrofolate reductase (MTHFR) deficiency

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Cystathionine synthase deficiency tx

dec. methionine, inc. cysteine, inc. B6, B12, and folate in diet)

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dec. affinity of cystathionine synthase for pyridoxal phosphate tx

inc. substantially B6 and inc. cysteine in diet

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Methionine synthase (homocysteine methyltransferase) deficiency tx

inc. methionine in diet

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Methylenetetrahydrofolate reductase (MTHFR) deficiency tx

folate in diet

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Homocystinuria presentation

All forms result in excess homocysteine.
H - HOMOCYstinuria: homocysteine in urine
O - Osteoporosis
M - Marfanoid habitus,
O - Ocular changes (downward and inward lens subluxation)
C - Cardiovascular effects (thrombosis and atherosclerosis - stroke and Ml)
Y - kYphosis

I - intellectual disability
F - fair complexion.

In homocystinuria, lens subluxated “down and in” (vs Marfan, “up and fans out”).

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Propionic acidemia - Findings:

Findings:

vomiting (vomit pathway)

S - seizures
H - hepatomegaly
A - acidosis (anion gap metabolic)
F - feeding (poor)
T -hypoTonia

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Von Gierke disease

(type I) sx

Severe fasting hypoglycemia

inc. Glycogen in liver and kidneys - hepatomegaly, renomegaly

Inc. blood lactate
inc. triglycerides
Inc. uric acid (Gout),

The liver does not regulate blood glucose.

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Tay-Sachs disease findings

R - hyperReflexia
A - hyperAcusis
N - Neurodegeneration (Progressive)
D - developmental delay
O - onion skin lysosomes
M - macula has  a "cherry-red" spot

No hepatosplenomegaly (vs Niemann-Pick).

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Tay-Sachs disease:
DEFICIENT ENZYME
ACCUMULATED SUBSTRATE

HeXosaminidase A

GM2 ganglioside

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Fabry disease findings

XR!
Early: the triad of episodic peripheral neuropathy, angiokeratomas, hypohidrosis.
Late: progressive renal failure, cardiovascular disease.

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Fabry disease
DEFICIENT ENZYME
ACCUMULATED SUBSTRATE

alfa -galactosidase A

Ceramide trihexoside (globotriaosylceramide)

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Metachromatic
leukodystrophy
DEFICIENT ENZYME
ACCUMULATED SUBSTRATE

Arylsulfatase A

Cerebroside sulfate

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Krabbe disease
DEFICIENT ENZYME
ACCUMULATED SUBSTRATE

Galacto-cerebrosidase (galactosyl-ceramidase)

Galactocerebroside, psychosine

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Gaucher disease DEFICIENT ENZYME ACCUMULATED SUBSTRATE

Glucocerebrosidase (beta-glucosidase); treat with recombinant glucocerebrosidase. Glucocerebroside

Niemann-Pick disease DEFICIENT ENZYME ACCUMULATED SUBSTRATE

Sphingomyelinase Sphingomyelin

Hurler syndrome DEFICIENT ENZYME ACCUMULATED SUBSTRATE

a -L-iduronidase Heparan sulfate, dermatan sulfate

Hunter syndrome DEFICIENT ENZYME ACCUMULATED SUBSTRATE

Iduronate-2-sulfatase Heparan sulfate, dermatan sulfate XR!

Metachromatic leukodystrophy - FINDINGS

Demyelination (central and peripheral) Ataxia Dementia.

Krabbe disease FINDINGS

N - Neuropathy (Peripheral) O - oligodendrocytes destruction D - developmental delay O - optic atrophy G - globoid cell

Gaucher disease FINDINGS

Most common: PHONe Booth with tissue paper ``` P - pancytopenia H - Hepatosplenomegaly O - osteoporosis N - necrosis (avascular, of the femur) e ``` Booth - bone crises Gaucher cells (lipid-laden macrophages resembling crumpled tissue paper).

Niemann-Pick disease FINDINGS

Progressive neurodegeneration, hepatosplenomegaly, foam cells (lipid-laden macrophages) "cherry-red" spot on macula.

Hurler syndrome FINDINGS

``` C - corneal clouding H - hepatosplenomegaly AR- AiRway obstruction G - gargoylism e D - Developmental delay ```

Hunter syndrome FINDINGS

Mild Hurler + aggressive behavior, no corneal clouding. "aggressive hunter needs to see the X"

Systemic 1° carnitine deficiency-

inherited defect in the transport of LCFAs into the mitochondria - toxic accumulation. It causes: weakness hypotonia hypoketotic hypoglycemia.

Medium-chain acyl-CoA dehydrogenase | deficiency- Pathophysiology

Dec. ability to break down fatty acids into acetyl-CoA - accumulation of fatty acylcarnitines in the blood. Treat by avoiding fasting.

Familial dyslipidemias pathogenesis

1LP (or C II), 2 LD (or apoB 100), 3 with no E , 4 gets more (VLDL)

Familial dyslipidemias with even number are

Familial dyslipidemias 1,4 cause

pancreatitis

Familial dyslipidemias 1,2,3 cause

xanthomas

Familial dyslipidemias 2 causes

corneal arcus + tendon xanthomas

Familial dyslipidemias 2,3

accelerated atherosclrosis

Familial dyslipidemias 4 is related to

insulin resistance

Familial dyslipidemia 1 has inc. blood level of

Chylomicrons, TG, cholesterol

Familial dyslipidemia 2 has inc. blood level of

Ila: LDL, cholesterol lib: LDL, cholesterol,VLDL

Familial dyslipidemia 3 has inc. blood level of

Chylomicrons, VLDL

Familial dyslipidemia 4 has inc. blood level of

VLDL, TG | Hypertriglyceridemia (> 1000 mg/dL)

Abetalipoproteinemia

``` FREE SAM: F - Fatty acid restriction (TX) R - Retinitis pigmentosa E - E Vit E (TX-oral) E - Enterocytes are lipid Layden ``` S - Spinocerebellar degeneration (due to vit E def.) A - Acantocytosis+ no Apo B48/100 M - MTP mutation (microsomal transfer protein) + Malabsorption.

weird reason for inc. synthesis of HDL

Alcohol

CARRIER MOLECULES for Acyl groups

CoA, lipoamide

Arsenic inhibits

lipoic acid.

Pyruvate dehydrogenase complex deficiency PATHOPHYSIOLOGY

Causes a buildup of pyruvate that gets shunted to lactate (via LDH) and alanine (via ALT). X-linked.

Pyruvate dehydrogenase complex deficiency FINDINGS

Neurologic defects Lactic acidosis Inc. serum alanine starting in infancy.

Pyruvate dehydrogenase complex deficiency TREATMENT

intake of ketogenic nutrients

Lactic acid dehydrogenase needs which cofactor?

Antimycin A:? | Azide:?

Antimycin A: complex 3 inhibitor | Azide: complex 4 inhibitor

PEPCK needs?

GTP

Cahill cycle | Cori cycle

Cahill cycle - Glucose & Alanin | Cori cycle - Glucose & Lactate

orotic aciduria vs. ornithine transcarbamylase def.

orotic aciduria - has megaloblastic aneamia ornithine transcarbamylase def. - has NH3 both have orotic acid in the urine (and blood)

Von Gierke disease tx:

frequent oral glucose/cornstarch; avoidance of fructose and galactose

Medium-chain acyl-CoA dehydrogenase | deficiency- findings

``` Causes: vomiting + CALLS + hypoketotic hypoglycemia. C - coma A - hyperAmmonemia L - lethargy L - liver dysfunction S - seizures ``` It can lead to sudden death in infants or children.

Biochemistry - Nutrition and Metabolism 2 Flashcards

(61 cards)