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24 Cards in this Set
- Front
- Back
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what is the pathophys of hyperammonemia?
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excess NH4 depletes a-ketoglutarate, leading to inhibition of TCA cycle
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What are the sx of ammonia intoxication?
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tremor, slurring of speech, somnolence, vomiting, cerebral edema, blurring vision
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What is the urea cycle?
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Degrades amino acids into amino groups and accounts for 90% of nitrogen in urine
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What are the three main derivatives of phenylalanine?
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Dopamine, NE, Epi
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What are the three main derivatives of tryptophan?
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Niacin, serotonin, melatonin
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What causes the musty odor of PKU?
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disorder of excess aromatic amino acids
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What is the pathphy of PKU?
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decrease in phenylalanine hydroxylase or tetrahydrobiopterin cofactor --> tyrosine becomes essential and phenylalanine builds up --> leads to excess phenylketones in urine
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What are the symptoms of PKU?
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mental retardation, growth retardation, fair skin, eczema, musty body odor
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What is PKU inherited?
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autosomal recessive - screened at birth
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What enzyme is deficient in alkaptonuria (ochronosis)?
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congenital deficiency of homogentisic acid oxidase in the degradative pathway of tyrosine
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What are the symptoms of alkaptonuria?
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Urine turns black on standing (alkapton bodies in urine), connective tissue is dark, may have debilitating arthralgias - Benign diease
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Variable inheritance of albinism is due to what genetic mechanism?
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locus heterozygosity
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Albinism is a congential deficiency one of which two items?
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1. Tyrosine (auto. Recess.) or 2. defective tyrosine transporters (decrease amounts of tyrosine and thus melanin)
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All forms of homocystinuria have wha inheritance pattern?
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autosomal recessive
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What are the 3 forms of homocystinuria and tx?
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1. Cystathionine synthase deficiency (decrease Met and increase Cys in diet) 2. Decrease affinity of Cystathionine synthase for pyridoxal phosphate (increase vitamin B6 in diet) 3. Mthionine synthase deficiency
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What are symptoms of homocystinuria?
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mental retardation, osteoporosis, tall stature, kyphosis, len subluxation, atherosclerosis
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What are pathphys of homocystinuria?
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results in excess homocysteine in the urine, cysteine becomes essential
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What are the sx of homocystinuria?
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mental retardation, osteoporosis, tall stature, kyphosis, lens subluxation, atherosclerosis (stroke and MI)
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The conversion of methionine to cysteine is dependent on which two vitamins?
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B6 (homocysteine to cystothionine) and B12 (homocysteine back to Met)
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What is the pathphys of cystinuria?
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inherited defect of renal tubular amino acid transporter for Cystine, Ornithine, Lysine, and Arginine in kidneys (COLA)
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What can cystinuria lead to?
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excess cystine in urine can lead to the precipitation of cystine kidney stones
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How is cystinuria treated?
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acetazolamide to alkalinize the urine
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Maple syrup urine disease is due to what defect?
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Blocked degradation of branced amino acid (Ile, Val, Leu) due to decreased a-ketoacid dehydrogenase --> increase alpha-ketoacids in the blood especially Leu
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What are the sx of maple syrup urine disease?
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CNS defecs, mental retardation and death
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