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17 Cards in this Set
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What is one enzyme that might be affected if pt presents with hemolytic anemia? Which cells are most affected, and what labs might you see?
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Deficiency in pyruvate kinase. Less ATP from glycolytic pathway is produced (-2ATP in conversion from PEP to pyruvate). Erythrocytes are most affected; increased levels in 2,3BPG in RBC's may be observed.
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What is the biochemical defect in lactose intolerance?
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Reduced protein expression of lactase complex on intestinal brush border cells. NOT a transcriptional problem, but translational.
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Enzyme deficiency in galactosemia?
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Deficiency in galactose-1-phosphate uridyl transferase. (look up - not sure where this was discussed, maybe glycogen storage disease)
Failure to thrive, vomiting, liver disease, mental retardation Galactose found in blood and urine - cannot convert gal to glu. Diagnose by finding low transferase activity in RBCs |
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Fructose intolerance enzyme?
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Aldolase B, which cleaves fructose 1,6 BP to DHAP and glycerol-3-phosphate (6C --> 3C)
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Why does arsenic poisoning cause death?
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Arsenic binds to lipoamide, a sulfhydrl group in PDC. Once lipoamide is bound, PDC no longer works, and the entry into TCA cycle is blocked.
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Thiamine (B1) deficiency affects which tissues? Why? What is B1 involved in?
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May affect HEART and BRAIN because these tissues produce much ATP from NADH produced from the PDC complex; PDC complex requires TPP (thiamine pyrophosphate)
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MCAD deficiency. Name enzyme. What do patients present with?
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Medium Chain Acyl Dehydrogenase. 10% of SIDS cases due to MCAD deficiency. located in the mitochondria (b-oxidation). Presents with severe hypoglycemia.
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Refsum's disease?
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Phytanic acid, accumulates due to defects in alpha oxidation (in mito, when CO2 is released after alpha carbon oxidized)
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What is ketoacidosis?
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fat mobilization due to low glucose --> ketone bodies (lower blood pH)
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Essential Fatty Acid Deficiency
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Humans cannot synthesize DB's past C10, so deficiency in omega3/6 results in Skin symptoms (dermatitis); skin is leaky to water; retarded growth; impaired reproduction; organ degeneration.
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Glycogen Storage Disease Type IA
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Affected enzyme is G-6-Phosphatase, which releases glucose into circulation. Results in hypoglycemia and hyperlipidemia (which results in hyperuricemia). Best treatment - cornstarch (slow glucose release), allopurinol to prevent uric acid buildup.
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Glycogen Storage Disease Type 5
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Muscle glycogen phosphorylase deficiency; glycogen cannot be released. Severe exercise intolerance; second wind phenomenon. Burgundy color urine after exercise – from breakdown of muscle tissue (myoglobin) Persistant weakness and muscle wasting
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Glycogen storage disease type 2 (Pompe's)?
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Affected enzyme is lysosomal acid alpha glucosidase. Results in glycogen accumulation in lysosomes. Frequent presentation - infantile onset, prominent cardiomegaly, hepatomegaly, death before 2 years of age due to cardiorespiratory failure.
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Affected enzyme in Glycogen Storage Disease Type 0?
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Glycogen Synthase. Shows fasting hypoglycemia, because not enough glycogen is produced. High blood ketones due to fatty acid oxidation, low alanine/lactate due to aa --> gluconeogenesis
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Type 3 glycogen storage deficiency caused by?
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Debranching defects. THREE-debranching sounds like TREE-debranching. Also called Cori disease. Glucose release from glycogen is therefore impaired (but can still release glucose through gluconeogenesis). Hyperlipidemia, hepatomegaly, hypoglycemia common. Lactate & uric acid is normal.
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Viable diet for Cori patients?
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High protein. Encourage gluconeogenesis through protein intake.
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Deficiency in glycogen storage disease type 4?
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Branching enzyme. Accumulation of abnormal glycogen; failure to thrive, death occurs before 5 years age.
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