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USMLE Biochem - glycogen and lysosomal storage diseases

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medmaestro's version from 2015-11-16 03:50

section 1

Question Answer
glycogen storage disease type IVon Gierkes
glycogen storage disease type 2Pompes ds.
glycogen storage disease type 3Coris ds.
glycogen storage disease type 4Andersen ds. (amylopectinosis)
glycogen storage disease type 5McArdle's ds.
glycogen storage disease type 6Hers ds.
glycogen storage disease type 7Tarui ds.
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Question Answer
deficient muscle PFK-1 has only 50% of normal activityTarui ds.(type 7)
exertional fatigue in childhood, nausea, vomiting, muscle cramps/weakness, hyperuricemia (d/t inc. degradation of muscle purine nucleotides), arthritis (d/t hyperuricemia), myoglobinuria, or frank anuria following high-intensity exerciseTarui ds. (type 7)
deficient enzyme is glucose 6 phosphataseVon Gierkes
findings include severe fasting hypoglycemia (d/t Glc stuck in liver), inc blood lactate, hepatomegaly (d/t inc glycogen in liver), hyperlipidemia (d/t hypoglycemia --> inc glucagon --> inc HSL --> fatty acid export into blood), inc. uric acid, short statureVon Gierkes
deficient enzyme is lysosomal alpha 1-4- glucosidasePompes ds.
cardiomegaly, muscle weakness, death by age 2Pompes ds.
deficient enzyme is debranching enzyme (alpha 1,6- glucosidase)Coris ds.
deficient branching enzymeAndersen ds (type 4) (amylopectinosis)
deficient glycogen synthesis --> short outer branches, with only 1 Glc residue at each outer branchCoris ds.
deficient glycogen synthesis --> very few branches, esp. toward periphery of glycogen moleculeAndersen ds (type 4) (amylopectinosis)
infantile hypotonia, cirrhosis, death by age 2Andersen ds (type 4) (amylopectinosis)
mild form of Von Gierke's [fasting hypoglycemia, inc glycogen in liver, hepatomegaly], with no inc. blood lactateCori's ds. (type 3)
deficient enzyme is skeletal muscle glycogen phosphorylaseMcArdles disease (type 5)
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Question Answer
deficient enzyme is hepatic glycogen phosphorylaseHers ds. (type 6)
hepatomegaly (d/t inc glycogen in liver), cirrhosis, MILD fasting hypoglycemia (mild b/c gluconeogenesis serves as backup)Hers ds. (type 6)
inc. glycogen in muscle (=biopsy), but cannot break it down, leading to painful muscle cramps, myoglobinuria with strenuous exerciseMcArdles disease
peripheral neuropathy of hands/feet, angiokeratomas, cardiovascular/renal diseaseFabrys disease
enzyme deficient is alpha-galactosidase AFabrys disease
accumulation of ceramide trihexosidaseFabrys disease
deficeint in glucocerebrosidaseGauchers disease
accumlation of glucocerebrosideGauchers disease
hepatosplenomegaly, aseptic necrosis of femur, bone crises, macrophages that look like crumpled tissue paperGauchers disease
deficient in sphingomyelinaseniemann-Pick disease
accumulation of sphingomyelinniemann-Pick disease
progressive neurodegeneration, hepatosplenomegaly, cherry-red spot on macula, foam cellsNiemann-Pick disease
deficient in hexosaminidase ATay-Sachs disease
accumulation of GM2 gangliosideTay-Sachs disease
progressive neurodegeneration, developmental delay, cherry-red spot on macula, lysosomes with onion skin, NO hepatosplenomegalyTay-Sachs disease
deficiency of B-galactocerebrosidaseKrabbes disease
accumulation of galactocerebrosideKrabbes disease
peripheral neuropathy, developmental delay, optic atrophy, globoid cellsKrabbes disease
deficeincy of arylsulfatase Ametachromatic leukodystrophy
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Question Answer
accumulation of cerebroside sulfatemetachromatic leukodystrophy
central and peripheral demyelination with ataxia, dementiametachromatic leukodystrophy
deficiency in alpha-L-iduronidaseHurlers syndrome, Scheie's ds.
accumulation of heparan sulfate, dermatan sulfateHurlers syndrome, Scheie's ds., Hunter's ds
difference btwn. Hurler's + Scheie'sHurler = short stature, Scheie = normal stature
developmental delay, gargoylism, airway obstruction, corneal clouding, hepatosplenomegalyHurlers syndrome
mild hurlers plus aggressive behavior, no corneal cloudingHunters syndrome
deficiency of iduronate sulfataseHunters syndrome
hepatosplenomegaly Niemann-Pick disease, Gaucher's, Hurler's
cherry-red maculaNiemann-Pick disease, Tay-Sachs ds.
phosphotransferase deficiencyI-cell ds.
deficient mannose-6-phosphate tagging for lysosomesI-cell ds
corneal cloudingHurler's, Scheie's, I-cell
corneal clouding, +/- mental retardation, no mannose-6-phosphate tagging for lysosomesI-cell ds.
corneal clouding, no mental retardation, inc. dermatan sulfateScheie's ds.
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Section 2

Question Answer
deficient with Von Gierkesglucose 6 phosphatase
hepatic steatosis, increased blood lactate, hepatomegaly, increased glycogen in liver, fasting hypoglycemiaVon Gierkes
deficiency is lysosomal alpha 1,4 glucosidasePompes disease
deficiency is alpha 1,6 glucosidaseCoris disease
painful muscle cramps, myoglobinuria with strenuous exerciseMcArdles disease
deficiency is alpha glucosidase AFabrys
accumulation of ceremide trihexosideFabrys
peripheral neuropathy of hands/feet, angiokeratomas, cardiovascular/renal diseaseFabrys
deficiency of glucocerebrosidaseGauchers
accumulation of glucocerebrosideGauchers
HSM, aseptic necrosis of femur, bone crisesGauchers
crumpled tissue paper looking cellsGauchers- macrophages
accumulation of sphingomyelinNiemann Pick
deficiency of sphingomyelinaseNiemann Pick
progressive neurodegeneration, HSP, cherry red spot on maculaNiemann Pick
foam cellsNiemann Pick
accumulation of GM2 gangliosideTay Sachs
deficiency of hexosaminidase ATay Sachs
progressive neurodegeneration, dev delay, cherry red spot on macula, no HSMTay Sachs
lysosomes with onion skinTay Sachs
deficiency of B galactocerebrosidaseKrabbes
accumulation of galactocerebrosideKrabbes
peripheral nerupathy, dev delay, optic atrophy, globoid cellsKrabbes
deficiency of arylsulfatase Ametachromatic leukodystrophy
accumulation of cerebroside sulfatemetachromatic leukodystrophy
central and peripheral demyelination with ataxia, dementiametachromatic leukodystrophy
deficiency of alpha-L-iduronidaseHurlers syndrome
accumulation of heparan sulfate, dermatan sulfateHurlers and Hunter's
developmental delay, gargoylism, airway obstruction, corneal clouding, HSMHurlers syndrome
deficiency of iduronate sulfataseHunters
mild hurlers plus aggressive behavior, no corneal cloudingHunters
2 lysosomal storage diseases x linkedHunters and Fabrys
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