Amino Acid Diseases

Question 1

Inherited defect in Na dependent transport of neutral amino acids by intestinal mucosa and renal tubules

Overall it causes a deficiency in trytophan

Answer 1

Hartnup Aminoaciduria disease

Question 2

Hartnup disease deficiency AA

Answer 2

Tryptophan!

Question 3

AMINOACIDURIA - INC URINE (neutral)
Elevated alanine, serine, threonine, valine, leucine, isoleucine, phenylalanine, tryptophan, tyrosine and histidine

NORMAL PLASMA AMINO ACID LEVELS

Answer 3

Hartnup Disease

Question 4

Unlike in Fanconi, these amino acids remain normal

Answer 4

Proline
Hyroxyproline
Arginine

Question 5

Cutaneous photosensitivity and psychiatric changes

Answer 5

Hartnup disease

Question 6

Treatment for Hartnup Disease

Answer 6

Nicotinic acid/nicotinamide since tryptophan is its precursor

High-protein diet in symptomatic disease

Question 7

Autosomal recessive

Inherited disorder of amino acid metabolism

Increased levels of homocysteine in the urine

Answer 7

Homocystinemia/uria

Question 8

Deficiency of cystathionine B-synthase
Deficiency of methylcobalamin formation
Deficiency of methyltetrahydrofolate reductase

Homocysteine is NOT REMETHYLATED to Methionine

Answer 8

Homocysteinemia/uria cystathione beta synthase deficiency

Question 9

Why does homocysteine accumulate?

Answer 9

Homocysteine is not methylated to methionine

Question 10

Treatment for homocysteinuria/emia

Answer 10

Pyridoxine B6 responsive form (50%) high dose

Pyridoxine B6 unresponsive form: restrict methionine and intake of cysteine supplementation

Question 11

Failure to thrive and developmental delay

Similar to Marfan’s in skeletal and ocular features

Increased methionine and homocysteine in body fluids

Answer 11

Homocysteinuria cystathione beta synthase deficiency

Question 12

Dislocation of the lens in Marfan’s happens

Answer 12

posteriorly

Question 13

Elevation of homocysteine levels predispose patient to

Answer 13

Clots

Stroke, MI

Question 14

Inherited disorder of branched chain AA metabolism

Inc levels of leucine, isoleucine and valine (can’t LIV) and corresponding oxoacid accumulate in body fluid

Deficiency of branched chain ketoacid dehydrogenase

Answer 14

MSUD branched chain ketoacid dehydrogenase deficiency

Question 15

Inc plasma/urine level of
leucine, isoleucine, valine and allisoleucine

DECREASED levels of plasma ALANINE

Urine precipitant test and neuroimaging (acute state) can show cerebral edema

Answer 15

MSUD branched chain ketoacid dehydrogenase deficiency

Question 16

MSUD deficient enzyme

Answer 16

Branched chain ketoacid dehydrogenase

Question 17

Increased metabolite in MSUD branched chain ketoacid dehydrogenase

Answer 17

Oxoacid

Question 18

Branched chain amino acids INCREASED in MSUD

Answer 18

Leucine
Isoleucine
Valine

Decreased ALANINE

Question 19

Hypertonicity, flaccidity, convulsion and hypoglycemia

Odor of maple syrup (urine, sweat, cerumen)

Answer 19

MSUD branched chain ketoacid dehydrogenase deficiency

Question 20

MSUD branched chain ketoacid dehydrogenase deficiency treatment

Answer 20

Frequent serum level monitoring

Low branched chain AA diet

If patient is acidotic, emergent hemodialysis or peritoneal dialysis

Liver transplant

Question 21

Avoid acidotic state in MSUD branched chain ketoacid dehydrogenase because acid build up in the brain causes creation of

Answer 21

GABA