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20 Cards in this Set
- Front
- Back
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What are the top 2 systems affected by mitochondrial disorders?
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#1 = PNS
#2 = CNS |
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Where do mutations occur in mitochondrial disorders?
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In the mitochondrial genome or nuclear genes encoding mitochondrial proteins.
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What results from mitochondrial disorders?
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Defects in the respiratory chain and oxidative phosphorylation.
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Why are mitochondrial disorders progressive and manifested first in the PNS and CNS?
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Because neurons have very high energy demand.
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Where are mitochondrial genes inherited from?
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Maternal
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What shows the progressive nature of mitochondrial defects?
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The fact that there is a THRESHOLD phenotypic expression of disease.
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When is the threshold phenotypic expression of disease reached in mitochondrial defects?
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When the mutation can no longer be compensated for by the coexisting wild type mtDNA.
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What causes polyglutamine diseases?
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Expansions of unstable trinucleotide repeats
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What are 9 neurodegenerative diseases caused by?
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CAG expansions
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What does CAG encode?
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Glutamine
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So Polyglutamine disease is a result of?
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CAG repeat expansions
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What are Polyglutamine diseases like in nature of onset and progression? When do they typically strike?
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-Progressive - neurons first dysfunctional, then loss occurs 10-20 yrs after onset of sx
-Strike in midlife |
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What deficits are seen in patients with polyglutamine disease?
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Both impaired MOTOR and COGNITIVE function
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Is the number of CAG repeats uniform in patients?
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No its polymorphic
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What does the number of repeats determine in polyglutamine diseases?
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-Age of onset
-Severity of phenotype |
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What happens with successive generations in families with polyglutamine diseases?
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The number of repeats expands and the age of onset and severity of phenotype gets early and worse.
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What type of transmission does this particularly show up in?
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PATERNAL
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What is this phenomenon known as?
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ANTICIPATION
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Why are polyglutamine diseases neurodegenerative?
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Because the expanded repeats form aggregates of protein!
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What is a putative way of treating Polyglutamine toxicity?
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Inhibiting Histone deacetylases, which prevents the formation of aggregates.
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