Renal--Biochem--Inborn Defects Of Nitrogen Metabolism Renal Biochem

Front 1

What is the result of total deficiency of urea cycle enzymes

Back 1

Death in utero, anyone living has only a partial deficiency

Front 2

Why is the loss of a urea cycle enzyme toxic?

Back 2

Creates hyperammonemia--It backs up all the way to ammonia which has toxic effects.

Front 3

What is the classic presentation of urea enzyme defect in infants?

Back 3

irritability, hypotonia (low muscle tone), lethargy, vomiting, ataxia (no coordinated muscle movement), delayed growth

Front 4

When can a urea cycle defect in adults or older children be seen?

Back 4

After a precipitating event such as feast

Front 5

What is the prognosis of untreated urea cycle defect?

Back 5

spasticity, mental retardation, coma, death

Front 6

Does product concentration change in deficiency?

Back 6

Increased pressure due to substrate concentration makes each enzyme more efficient causing little change in product concentration

Front 7

CPSD- what is it, diagnosis

Back 7

1) Enzyme def STEP 1 CPS I
2) ONLY hyperammonemia diagnose by eliminating all the other possibilities

Front 8

OTCD- what is it, diagnosis

Back 8

1) Enzyme def STEP 2 OTC
2) hyperammonemia, oratate back up in blood (carbamoyl phosphate leaks into cytoplasm CPS II causes pyrimidine cycle form, oratate produced)

Front 9

ASD- what is it diagnosis

Back 9

1) Enzyme def STEP 3, AS
2) elevated citrulline in blood, urine

Front 10

ALD- what is it, diagnosis

Back 10

1) Enzyme def STEP 4, AL def
2) elevated argininosuccinate in blood and urine

Front 11

AD, what is it? diagnosis?

Back 11

1) arginase deficiency
2) elevated arginine in blood/urine

Front 12

What is the effect of dialysis?

Back 12

treat inborn defects by reducing blood ammonia levels

Front 13

What does intravenous sodium benzoate phenylacetate do?

Back 13

Treatment for inborn defect, these compounds bind random aa and excrete them

Front 14

What defects are treated via arginine supplementation, how?

Back 14

ASD and ALD. Both citrulline and arginosuccinate can be excreted by the kidney so you can rid of ammonia, however in order to regenerate ornithine, you must supply additional arginine

Front 15

When would supplying arginine not treat ASD ALD?

Back 15

If there was also arginase deficiency

Front 16

What is the affect of levulose?

Back 16

Acidifies gut so ammonia binds to acid moeities to treat inborn defects

Front 17

What is the effect of antibiotics

Back 17

kills some gut bacteria therefore minimizing ammonia production by these bacteria to treat inborn defect