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Biochem Block 1 > Block 1 Diseases > Flashcards

Block 1 Diseases Flashcards

1
Q
  • spongiform degeneration & astrocytic gliosis in CNS
  • prion aggregates and amyloid plagues are seen; these are resistant to proteolytic degradation
  • What disease?
A

Prion Disease

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2
Q

-spongiform degeneration & astrocytic gliosis in CNS
-prion aggregates and amyloid plagues are seen; these are resistant to proteolytic degradation
What mutation?

A

Infectious or sporadic mutation from PrPc → PrPsc

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3
Q

Between PrPsc and PrPc, which is compose of mostly β-sheets and which of α-helixes

A

PrPsc is mostly composed of β-sheets whereas the normal protein has mostly α-helixes.

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4
Q

Consumption of meat from an animal affected with prion disease leads to entry of PrPsc

A

Mad Cow

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5
Q
  • prion disease in humans
  • 2 types; 1) sporadic CJD (85%) due to somatic cell mutation or rare spontaneous refolding , 2) familial CJD due to autosomal dominant inherited mutation
A

Creutzfeld-Jakob Disease

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6
Q

What decade does familiar CJD manifest?

A

4th decade

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7
Q

-accumulation of Aβ42 rich plaque in the brain; this is toxic

A

Alzheimer’s Disease

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8
Q

-accumulation of neurofibrillary tangles inside the neurons, the key component of this tangle is hyperphosphorylated tau proteins

A

Alzheimer’s Disease

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9
Q

-Dopamine depletion in the neostriatum due to degeneration of dopaminergic nigrostriatal neurons in substantia nigra pars compacta

A

Parkinson’s Disease

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10
Q

What insoluble protein is seen in Parkinson’s Disease?

A

α-synuclein

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11
Q

-insoluble protein α-synuclein accumulates inside the neurons forming inclusions called Lewy bodies

A

Parkinson’s Disease

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12
Q

What hemoglobin is seen in Sickle Cell Trait?

A

Hb AS

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13
Q

single nucleotide change in one of the β globin genes at 6th position (Glu→Val)

A

Sickle Cell Trait

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14
Q

What hemoglobin is seen in Sickle Cell Anemia?

A

Hb SS

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15
Q

single nucleotide change in both of the β globin genes at 6th position (Glu→Val)

A

Sickle Cell Anemia

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16
Q

-Glutamic acid→Lysine in 6th position in β chain

A

Hemoglobin C

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17
Q

-Compound heterozygosity: 1 β-globin with sickle cell mutation and one mutant for HbC; Glu→Lys in one beta and Glu→Val in the other

A

Hemoglobin SC

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18
Q

-1 sickle β-globin and the other β-globin is absent

A

Sickle beta (o) thalassemia (Sβ0 thalassemia)

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19
Q
  • > 90% HbS, splenomegaly and vaso-occlusive crisis seen
A

Sickle beta (o) thalassemia (Sβ0 thalassemia)

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20
Q

-1 sickle β-globin and the other β-globin is in decreased amounts

A

Sickle beta (+) thalassemia (Sβ+ thalassemia)

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21
Q
  • > 60% HbS, splenomegaly and vaso-occlusive crisis seen
A

Sickle beta (+) thalassemia (Sβ+ thalassemia)

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22
Q
  • α-globin is absent (non is synthesized)
A

α0 thalassemia

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23
Q

-some α-globin is synthesized

A

α+ thalassemia

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24
Q

one of the 4 α-globin gene is deleted. These individuals are called silent carriers of α-thalassemia

A

α-thalassemia-2 trait

25
Q

-two genes are deleted. These individuals are called α-thalassemia trait.

A

α-thalassemia-1 trait

26
Q

3 genes deleted – mild to moderate hemolytic anemia

  • HbA production is only 25-30% normal
  • Unpaired genes accumulate and are soluble enough to form β4 tetramers called HbH → forms inclusions in erythroblasts and precipitates in circulating RBC.
A

HbH (β4) disease

27
Q

no clinical manifestations noted in this thalassemia

A

α-thalassemia-2 trait

28
Q

have thalassemia intermedia characterized by moderately severe hemolytic anemia but milder ineffective erythropoiesis

A

HbH (β4) disease

29
Q
  • all 4 genes are deleted
  • all 4 genes are gamma; no physiologically useful hemoglobin is produced beyond embryonic stage
  • almost no O2 is delivered to fetal tissues, causing tissue asphyxia, edema, congestive
A

Hydrops fetalis w/ Hb Barts (γ4)

30
Q

-Excess γ-globin forms tetramers called Hb Barts (γ4), which has a very high O2 affininity

A

Hydrops fetalis w/ Hb Barts (γ4)

31
Q

-β-globin gene has 2 copies; 1 on each chromosome 11

A

β-thalassemia

32
Q

-1 β-globin gene is defective

A

β-thalassemia trait/minor

33
Q
  • both β-globin genes are defective

- unpaired α-globins accumulate and form toxic inclusion bodies → kill proerythroblasts and ↓ RBC life-span

A

β-thalassemia major (Cooley anemia)

34
Q

Commonly seen in patients of Mediterranean descent

A

β-thalassemia disorders

35
Q
  • due to oxidation of Fe2+ (ferrous ion) →Fe3+ (Ferric ion), which cannot bind O2
  • can be acquired by exposure to oxidizing drugs (nitrates) and chemicals
A

Methemoglobinemia

Hb M

36
Q

dusky discoloration to skin

  • chocolate-colored blood
  • anemia
  • presence of Heinz bodies
  • tissue hypoxia
  • anxiety, headache, dyspnea, and rarely coma or death
    tx: methylene blue
A

Methemoglobinemia

Hb M

37
Q
  • Chipmunk faces (↑ erythropoietin & bone marrow expansion)
  • pathological fractures → bone thinning
  • severe hemolytic anemia
  • hepatosplenomegaly
  • iron overload
  • usually fatal by age 30
A

β-thalassemia major (Cooley anemia)

38
Q
  • Mutation in either proα1 chain gene or proα2 chain gene of type 1 procollagen (COL1A1 & COL1A2 genes)
  • Single base substitution of glycine with a bulkier aa → compromises structural integrity of triple helix → disruption of helix folding and retention of mutant trimmers in ER
  • Formation of insoluble aggregates in the ER that are degraded
A

Osteogenesis Imperfecta

39
Q
  • severe ↓ in bone mass → Brittle bones
  • “popcorn-like” deposits of mineral in x-rays of ends of long bones
  • blue sclera
  • dentinogenesis imperfecta→amber, yellow/brown teeth
  • progressive hearing loss
  • family history
A

OI

40
Q

Mutation in structural gene for collagen

A

Ehlers-Danlos Syndrome

41
Q

What are the mutated genes in EDS 1 and 2?

A

Mutation in COL5A1 & COL5A2 (type 5 collagen), COL1A1 and COL1A2 (type 1 collagen)

42
Q

What are the mutated genes in EDS 3?

A

mutation in TNXB gene →encodes tenascin X. Normal function of tenascin is to regulate assembly of collagen fibers

43
Q

What are the mutated genes in EDS 4?

A

mutation in COL3A1 (type 3 collagen)

44
Q
  • hyperelastic skin; skin is easily torn or scarred, “rubber person” syndrome and “cigarette paper” scares
  • hypermobile joints; mild to unreducable dislocations of joints;
  • easy bruisibility
  • hernias
  • mitral valve prolapse
  • degenerative arthritis
  • scolilosis
A

Ehlers-Danlos Syndrome

45
Q
  • deficiency of Vit. C/ascorbic acid, which is required for coenzyme for prolyl hydroxylase and lysyl hydroxylase in collagen formation, so you don’t get hydroxylysine or hydroxyproline or h-bonding, so triple-helix is not stabilized
  • collagen is improperly formed
A

Scurvy

46
Q
  • skin changes with roughness
  • easy bruising and petechiae
  • gum bleeding
  • loosening of teeth
  • poor wound heeling
  • corkscrew hair
A

Scurvy

47
Q

Gene mutated in Menkes Disease?

A

ATP7A

48
Q
  • X-linked defect in copper binding P type ATPase
  • Low serum Cu levels & too much Cu deposit in intestinal cells
  • Lysyl oxidase is dependent on Cu cross-linking
A

Menkes Disease

49
Q
  • Sparse & Coarse brittle hair
  • growth failure
  • deterioration of nervous system
A

Menkes Disease

50
Q

Glutamic acid → Lysine
-Polymerize in Liver cells & cannot inhibit elastase
What gene is mutated?

A

α1-Antitrypsin

51
Q
  • ↓ A1At activity in the blood and lungs, and deposition of excessive abnormal A1At protein in liver cells
  • Severe A1At deficiency causes panacinar emphysema or COPD in adult life; cigarette smoke directly inactivates A1At by oxidizing essential methionine residues to sulfoxide forms, ↓ enzyme activity by a factor of 2000
A

α1-Antitrypsin Deficiency

52
Q
  • shortness of breath
  • wheezing
  • rhonci
  • impaired liver function
  • Autosomal recessive
  • leading cause of liver transplantation in newborns
A

α1-Antitrypsin Deficiency

53
Q

Mutation in Marfans?

A

FBN1 mutation

54
Q

Fibrillin-1 binds to TGFβ → unable to exert activity, so ↑TGFβ ↓ Fibrillin-1
-FBN1 usually encodes for fibrillin-1 → proper formation of ECM

A

Marfan’s

55
Q
  • S → Skeletal (long limbs, scoliosis, joint flexibility)
  • H → Heart (aorta dilatation, mitral or aortic valve prolapse)
  • E → Eyes (ciliary zonules, dislocation of lens)
  • spontaneous pneumothorax
A

Marfan’s

56
Q

-Defective transport of cysteine – oxidative condensation of two cysteins in intestines and kidney

A

Cystinuria

57
Q

inherited Methemoglobinemia is caused by defect in what?

A

NADH-cytochrome b5 reductase

58
Q

In most of the hemoglobin M, tyrosine has been substituted for either the proximal or the distal histidine. This results in reduced capacity of the enzymatic machinery of the erythrocyte to efficiently reduce the iron to the divalent form and thus predisposes to methemoglobinemia.

A

-

59
Q
  • methylene blue- converts from ferric to ferrous
  • hemoglobin M is when tyrosine takes place of prox or distal histidine and cant turn ferric back to ferrous
  • know that fbn1 binds to latent form of tgfb
  • cigarette smoke inactivates a1at by oxidizing methionine resides to sulfoxide forms
  • know that a1at gene mutation = glutamic acid to lysine ( GAG to AAG)
  • know that desmosine crosslinks give elastin it’s elastic property
A

-

Biochem Block 1 (10 decks)

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