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20 Cards in this Set

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