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30 Cards in this Set
- Front
- Back
What is the inheritance pattern for Huntington's Disease?
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autosomal dominant with anticipation
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HD is due to an expansion of the ________ gene on chromosome ____.
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huntington; 4
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T/F: HD demonstrates a low degree of penetrance
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False
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Signs/Symptoms of HD
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chorea (cardinal manifestation)
behavioral and personality disorders dystonia dysarthria dementia |
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HD has been hypothesized to result from a ___ of function mutation.
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gain
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All individuals who have the HD mutation will manifest the disease by the time they are ___ years old, with 50% of HD patients expressing their symptoms by age __.
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80; 45
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What are the symptoms of Juvenile HD?
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rigidity, tremor, dystonia, myoclonic epilepsy, dementia
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HD patients have an expanded _ _ _ allele.
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CAG
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An individual with __ or more repeats will likely develop HD sometime in their life.
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40
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Someone with fewer than __ repeats will not likely develop HD.
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36
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What are some non-translated trinucleotide repeat disorders?
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Fragile X & Myotonic dystrophy
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What are some translated trinucleotide repeat disorders?
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Spinobulbar muscular atrophy (Kennedy syndrome)
Spinocerebellar ataxia (type 1 & 7) HD Dentatorubropallidoluysian atrophy (DRPLA) Machado-Joseph |
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Expanision of repeats in HD occurs in ___________ transmission.
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Paternal
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What area of the brain is most affected by HD?
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caudate
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What part of the brain (specifically) is affected earliest in HD?
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the tail of the caudate
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What kind of neurons are lost in the caudate and putamen in HD?
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medium spiny neurons
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In what order are the types of medium spiny neurons lost in HD?
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1st: enkephalinergic neurons
2nd: Substance P neurons (lost only later in disease) |
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The striatum excites the globus pallidus via which pathway?
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indirect (direct inhibits)
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The enkephalinergic neurons in the striatum project to the globus pallidus via the direct or indirect pathway?
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indirect
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What is the simplified pathway of basal ganglia circuitry involved HD?
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cerebral cortex excites striatum -->
striatum inhibits medial globus pallidus (via direct or indirect pathway) --> project to thalamus --> projects back to cortex |
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Is the pathway from the cortex to the basal ganglia excitatory or inhibitory?
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excitatory
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In HD there is a preferential loss of neurons to the _________.
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lateral globus pallidus
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T/F: In Juvenile HD there is a preferential loss of neurons to the medial globus pallidus.
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False: in Juvenile HD there is equal loss to lateral and medial globus pallidus
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What are two hypotheses about HD pathophysiology?
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1. excitatory amino acids are involved
2. mitochondrial energy metabolism may contribute to nerve degeneration |
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In what tissue is the protein that the huntington gene encodes found?
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all tissue
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Where in the cell is the protein encoded by the huntington gene found?
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cytoplasm
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Do HD brains show an increase or decrease in the huntington protein?
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decrease
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What are some potential therapies for HD (demonstrated in mouse models)?
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creatine
ciliary neurotrophic factor environmental enrichment |
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How many CAG repeats does a normal person have?
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less than 26
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What are some current treatment options for chorea?
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Benign neglect is best
neuroleptics occupational and physical therapy speech therapy medications (atypical antipsychotics, amantidine, tetrabenazine) |