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12 Cards in this Set
- Front
- Back
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Hoocysteinuria is a defect in which enzyme?
where are the mutations usually found? what is usually the treatment for the 2 main phenotypes of homoscytinuria |
cystathionine B synthatse
B6 responsive: B6 and folic acid mutations @ or near active site non-b6 responsive: decrease methionine intake and increase cystine intake |
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Glycogen storage type I is defect in which enzyme?
where is the enzyme found? where are the mutations found? how do you treat it? |
G6Pase in ER membrane
mutations usually found on lumenal surface near active site result: on glucose to export treatment: contant glucose infustions secondary: statis (hyperlipidemia) and allpurenol (gout) |
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what is the pathophysiology of cystinuria? what is the defective transporter/defective gene?
what is the phenotype? treatment? |
autosommal recessive
inability to transport cystine into PCT (which gets broken into two cysteines to be transported into blood) mutation of SLC3A1 (heavy subunit of transporter) M467T mutation (heavy subunit doesn't localize to cell membrane to hook up with light chain) phenotype: kidney stones (cystine not very soluble-->clumps) treatment: hyrdartion and penicillamine (chelating agents that binds cystine and increases solubility) |
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I cell desase
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N-acetylglucosamine-1-phosphoptransferase defect
lysosomal storage disease: defective mannose-6-P tag inclusion bodies! |
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Tay sachs
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B-hexoaminidase A
lysosomal storage disease: incrase ganglisidoses in brain; increase in glial cell numbers and abnormal dendritic growth |
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Pompe's disease
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alpha-D-glucosidase (acid glucosdiase)
lysosomal storage disease: increase in glycogen concentration |
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common mutation for acute infantile tay-sachs?
clinical phenotype? |
insertion @ exon 11 (frameshift) in gene that codes for Beta-hexosaminidase A
causes blindness (cherry red spot deposits in retina) |
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hereditary Hemochromocytosis? basics
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autosomall recessive
loss of HFE function-->decrease synthesis in Hepcidin results in increase release of iron into blood and saturation of transferrin===>accumulation of iron |
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how does serum iron regulate iron release into blood?
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high serum iron increase hepcidin, which decreases iron release via blockage of basolateral ferroportin (FPN)
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how is hepcidin transcription regulated?
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when iron-transferrin complex bind TfR1 on apical hepatocytes-->TFR2 is free to bind HFE
the functional complex (HFE-TFR2) acts on nuclease to increases hepcidin transcription at HAMP gene |
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normal hepcidin fn.?
abnormal? |
normal: released by liver, blocks iron release from duodenal enterocytes; stored as ferritin
abnormal: constitutive iron release-->spills into parenchymal tissues-->oxidative damage |
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how does vitamin c affect iron absorption?
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increases it!
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