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USMLE MS > Metabolic storage dz > Flashcards

Metabolic storage dz Flashcards

1
Q

Alkaptonuria. enzyme, accumulated substrate, symptoms

A

homogentisate oxidase, on the pathway of tyrosine to fumarate
homogentisate
black urine/cartilage, degenerative arthritis (homogentistic acid is toxic to cartilage)

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2
Q

Galactosemia, enzyme, accumulated substrate, symptoms

A

GALT (galactose 1 phosphate uridyltransferase
galactose 1 phosphate (toxic to liver and CNS, galactose in urine, Galactitol (lens damage)
mental retardation, cirrhosis, hypoglycemia (due to decreased gluconeogenic substrate), cataracts. also phosphate depletion, cant do gluconeogen or glycolysis

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3
Q

galactokinase deficiency. enzyme, accumulated substrate, symptoms

A

galactokinase.
galactilol accumulates.
infantile cataracts, galactose in blood and urine. failure to track objects, no social smile

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4
Q

hereditary fructose intolerance. enzyme, accumulated substrate, symptoms

A

aldolase B.
fructose 1P. decreases available phosphate, inhibits gluconeogenesis and glycolysis.
sx after fruit, juice, honey. reducing sugars in urine. hypoglycemia, jaundice cirrhosis, vomiting.

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5
Q

essential fructosuria. enzyme, accumulated substrate, symptoms

A

fructokinase

fructose is not trapped in cells, so asx. fructose is in blood and urine.

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6
Q

homocysteinuria with increased methionine. enzyme, accumulated substrate, symptoms

A

cystathione synthase
homocysteine and methionine accumulate
mental retardation, vessel thombosis, lens dislocation (down and in), arachnodactyly (long slender fingers). Tall kyphotic, osteoporosis

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7
Q

homocysteinuria but with decreased methionine. enzyme, accumulated substrate, symptoms

A 
homocysteine methyltransferase
accumulate cysteine (?). tx by giving methionine in diet
mental retardation, vessel thombosis, lens dislocation (down and in), arachnodactyly (long slender fingers)
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8
Q

maple syrup urine dz. enzyme, accumulated substrate, symptoms

A

branched chain alpha ketoacid dehydrogenase (which needs thamine, B1)
leucine, valine, isoleucine and their ketoacids
mental retardation, seizures, feeding problems, sweet smelling urine (burnt sugar)

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9
Q

pheylkentonuria. enzyme, accumulated substrate, symptoms

A

phenylalanine hydroxylase.
phenylalanine, phenylpyruvate/acetate/lactate
mental retardation, microcephay, mousy odor, decreased pigmentation, eczema. when pregnant, PKU mom must restrict phy from diet (microcephaly, heart, brain)
tyrosine is essential now

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10
Q

malignant PLU enzyme, accumulated substrate, symptoms

A

dihydropterin reductase
phenylalanine and biproducts.
decreased neurotransmitters! (tyrosine and tryptophan need BH4. ) neurologic issues despite diet therapy.

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11
Q

McArdle’s disease. enzyme, accumulated substrate, symptoms

A

muscle glycogen phosphorylase.
glycogen in muscle
muscle fatigue, no lactic acid with exercise

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12
Q

Pompe disease. enzyme, accumulated substrate, symptoms

A

alpha 1,4 gucosidase (lysosomal enz)
glycogen
cardiomegaly and early death

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13
Q

von gierke’s dz. enzyme, accumulated substrate, symptoms

A

glucose 6 phosphatase
glycogen in liver, and G6P
severe fasting hypoglycemia, increased blood lactate, hepatomegaly. large kidneys,

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14
Q

gaucher’s dz, enzyme, accumulated substrate, symptoms

A

glucocerebrosidase
glucocerebroside
HSM, pancytopenia, aseptic necrosis of femur. crumpled tissue paper macrophages. tx with recombinant glucocerebrosidase

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15
Q

Cori Dz. enzyme, accumulated substrate, symptoms

A 
debranching enzyme (alpha 1,6 glucosidase)
glycogen
normal blood lactate levels, gluconeogenesis is intact (compare to von gierke's).
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16
Q

Fabry dz. enzyme, accumulated substrate, symptoms

A

alpha galactosidase A (x linked)
ceremide trihexoside
peripheral neuropathy of hands feet. angiokeratomas, cardiovasc and renal dz.

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17
Q

neimann-pick dz. enzyme, accumulated substrate, symptoms

A

sphingomyelinase
sphingomyelin
progressive neurodegeneration. HSM (compare to tay sachs), cherry red macula. foam cells (lipid laden macrophages)

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18
Q

Tay sachs. enzyme, accumulated substrate, symptoms

A

hexosaminidase A
GM2 ganglioside
progressive neurodegeneration. No HSM (compare to neimann pick). cherry red macula. lysosome with onion skin

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19
Q

krabbe dz (globoid cell leukodystrophy). enzyme, accumulated substrate, symptoms

A

galactocerebrosidase
galactocerebroside, psychosine
peripheral neuropathy, developmental delay. optic atrophy, globoid cells

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20
Q

metachormatic leukodystrophy. enzyme, accumulated substrate, symptoms

A

arylsulfatase A.
cerebroside sulfate
central and peripheral demyelination, ataxia and dementia

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21
Q

hurler syndrome. enzyme, accumulated substrate, symptoms

A

alpha-L- iduronidase (AR)
heparan sulfate, dermatan sulfate
developmental delay, gargoylism. airway obstruction, corneal clouding (compare to hunter), HSM

22
Q

hunter syndrome. enzyme, accumulated substrate, symptoms

A

Iduronate sulfatase (XR)
heparan sulfate, dermatan sulfate (less severe than hurler)
MILD developmental delay, airway obstruction, HSM. No corneal clouding (compare to hurler)
Hunters have to see

23
Q

X linked metabolic/lysosomal storage dz

A

Hunter, Fabry, G6PD deficiency. OTC deficiency

24
Q

G6PD deficiency. enzyme, symptoms

A

glucose 6 phosphate dehydrogenase
can’t make NADPH.
hemolytic anemia (fava beans, sulfonamides, primaquine, antiTB drugs, infection, all due to RBCs being unable to deal with oxidizing agents). increased malaria resistance.

Heinz bodies (oxidized hemoglobin percipitated in RBC
bite cells from phagocytic removal of heinz bodies
25
Q

N acetylglutamate deficiency.

A

Hyperammonemia. looks just like carbamoyl phosphate synthetase I deficiency. increased ornithine with nml urea cycle enzymes suggests N acetylglutamate deficiency

26
Q

OTC, orinithine transcarbamylase deficiency

A

most common urea cycle disorder. this is the only X linked recessive one. Increased orotic acid in blood and urine due to shunting of cabamoyl phosphate to pyrimidine synthesis.
hyperammonemia, present in first few days of life. decreased BUN. no megaloblastic anemia (unlike orotic aciduria)

27
Q

carnitine deficiency.

A

can’t transport long chain fatty acids into mitochondria,

weakness, hypotonia, hypoketotic hypoglycemia.

28
Q

Acyl CoA dehydrogenase deficiency

A

increased dicarboxylic acids, and decreased glucose and ketones. decreased acetyl coA, low fasting glucose.

29
Q

X linked dominant diseases (in general)

A

Alport’s disease (hereditary glomerulonephritis with nerve deafness.)
Vitamin D resistant rickets (defect in renal and GI absorption of phosphate, leading to osteomalacia)

30
Q

Chediak higashi syndrome

A

lysosomal trafficking regulator gene (LYST), microtubule dysfuntion in phagolysosome fusion.

pyogenic staph and strep (defective PMN function; alibinism (melanocytes can’t get the pigment out to the keratinocyes); peripheral and cranial neuropathy, nystagmus (soma can’t get proteins out to the axon ends).

giant granules in PMN near golgi, and plts. pancytopenia becuase you can;t move cellular products during cell division, mild coag issues

31
Q

digeorge

A

Chr 22 deletion, maldeveloped 3rd and 4th pouch

thymic, parathyroid hypoplasia, abn facies, conotruncal cardiac issues (TOF, truncus) as well as aortic arch issues, tetany; recurrent viral fungal infections

32
Q

Wiskott aldrich

A

X linked, WAS gene mutation. T cells can’t recorganize actin cytoskeleton

thryomobytopenic purpura; eczema; recurrent infection.

increased risk of autoimmune and malig. Increased IgE and A, nml to low G and M

33
Q

Ataxia telangiectasia

A

ATM gene, leading to DNA ds breaks and arresting cell cycle.

cerebellar issues (Ataxia), telangiectasias (spider angiomas), IgA deficiency. Thymic hypoplasia

Elevated AFP, low IgA IgG IgE

34
Q

Hyper IgM syndrome

A

defective CD40L on Th cells, no class switching. X linked

severe pyogenic infections early: PCP, Cryptosporidium, CMV

35
Q

SCID

A

IL2R X linked defect. or adenosine deaminase deficiency leading to adenosine which is toxic to lymphocytes. or an MHC II defect.

chronic diarrhea, thrush. bacterial, viral, fungal and protozoal!! No thymic shadow, decreased T cell receptor excision circles (?)

36
Q

Leukocyte adhesion deficney

A

integrin (CD18) deficiency. impaired migration and chemotaxis.

bacterial and mucosal infections, NO PUS. delayed cord separation. impaired wound healing.

increased PMNs in blood but not at site

37
Q

Chronic granulomatous dz

A

NADPH oxidase defiency, no respiratoy burst. catalase postive bugs!

PLACESS(N)
pseudomonas, listeria, apergillus, candida, ecoli, staph aureus, serratia, and nocardia

negative NBT. can still use peroxide made by bugs to make bleach, but not in catalase positive bugs!

38
Q

Myeloperoxidase deficiency

A

increased risk for candida infections, nml NBT. they are equally succeptible to staph and strep, for example. can’t make bleach

39
Q

X linked agammaglobulinemia (bruton)

A

BTK defect, tyrosine kinase, no B cell maturaion. (increased in Boys)

bacterial, giardia, enteroviral infections after 6 mo. nml CD19 cell count. absent or scanty lymph nodes and tonsils

40
Q

Selective IgA deficiency

A

most common. many pts with Celiac dz may have it. Mostly ASX. recurrent sinopumonary infections, like otitis media, sinusitis, bronchitis, pneumonia.

increased mucosal, esp viral. sx if also has IgG2 deficiency.

anaphylaxis to IgA containing products. do not treat with gamma globulin becuase it may increase formation of anti IgA antibodies. autoimmune dx,

41
Q

common variable immunodeficiency

A

defect in B differentiaion (many causes in including T helper cell issues)

increased risk of autoimmune, dx, brochiectasis, lymphoma, sinopulmonary.

42
Q

IL 12 defciency

A

decrased Th1 resoonse. myobacterial and fungal. may present after BCG vax. decrased IFN gamma

43
Q

hyperIgE

A

Autosomal dom. deficient Th17 due to stat3 mutation. impaired recruitment of PMNs to site.

coarse face, staph abcesses, retained primary teeth, increased IgE, derm issues like eczema

44
Q

chronic mucocutaneous candidiasis

A

T cell dysfuntion.

45
Q

wolf parkinson white

A

sudden cardiac death in otherwise healthy young person. EKG shows abnormality of AV cardiac conduction, no association with gross morphological changes in ventricles. small accessory AV impulse conduction pathway, anatomically separate from AV node.

46
Q

Lesch Nyhan’s dz

A 
HGPRT deficiency, X linked recessive 
normally converts IMP and guanine to GMP.
failure of purine salvage. 
Hyperuricemia
Gout
Potential for self harm
retardation (developmental delay)
hypoTonia

enzymes for devono synthesis of purines (not pyrimidines) are revved up.

47
Q

porphyria cutanea tarda

A

deficiency in Uroporphyrinogen decarboxylase. (can also be a deficiency in COPRO oxidase, PROTO oxidase or ferrochelatase

build up of porphyrins and porphyrinogens leads to photosensitivity, and blistering

48
Q

actue intermittent prophyria

A

porphobilinogen deaminase, aka HMB synthase, aka uroporphyrinogen I synthase
accumulate ALA, corporphobilinogen

Painful abdomen
port wine urine
polyneuropathy
psychological disturbances
percipitated by drugs, alcohol, starvation

Tx with glucose and heme, inhibiting ALA synthase

49
Q

Hartnup dz

A

defect in enterocyte apical transport for absorbing neutral aromatic amino acid (tryptophan)

ataxia, pellagra like rashes, loose stools

give them niacin!

50
Q

I cell dz

A

issue in posphorylating mannose at 6 position, cant target to lysosomes

coarse facial features, clouded cornea, resitricted joint movement, high plasma levels of lysosomal enzymes. foten fatal i nchildhood

USMLE MS (4 decks)

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