Week9_2002.pdf

Huntington’s Disease or Huntington’s Chorea
I. Symptoms : Cognitive and movement disorder.
Chorea (Greek): to dance.
Named after _______________________, an American physician in 1872.
Four (4) hallmark clinical signs:1) Involuntary movements: __________________________________ ______________________________________________________ - initially can resemble normal movements (especially if afflicted individual incorporates those involuntary movements into “normal -looking actions”).
- gives impression of restlessness.
- eventually results in facial grimacing, slurred speech, clumsy hands, unsteady walking, and abnormal posture.
2) Rigidity : ______________________________________________ 3) Bradykinesia: __________________________________________ ___________________________________________________________________________________ 4) Cognitive deficits and Dementia: ___________________________ ____________________________________________________________________________________________________________ - affected individuals may be describes as impulsive, erratic, difficult, uninhibited, and depressed (may increase alcohol drinking).
II. Etiology :
Unlike Parkinson’s disease, Huntington’s disease has a strong ______
component.
- disease has been linked to a family in a southern England town
(Bures) in the early 17th century (1630).
- however, their appears to be family histories untraceable to En gland suggesting a low but regular mutation frequency for this disease.
- ________________ that is lethal on average 17 -20 years after onset.
- usually first experienced ____________________________.
- approximately 30,000 individuals are diagnosed with Huntington’s - some individuals express the symptoms much earlier, during childhood, which has been linked to ____________________ of the gene; these show a faster rate of progression, with increased rigidity.
- maternal transmission of the Huntington’s gene produce a later occuring onset with milder, slower progression.
- gene associated with Huntington’s disease discovered in 1993.
- it is an ___________________ gene disorder passed down from the - linked to short arm of ________________. - therefore, children of one Huntington carrying parent have a 50 % chance of inheriting the disease (whether they are male or female).
Question. Would you prefer to know, given that one of your parent develops Huntington’s disease, whether you carry the gene or not ? - in normal individual, a _____________________ (cytosine-adenine- guanine), is normally found approximately 26 times as part of a normally occurring gene.
- in individuals with the Huntington’s gene, this CAG sequence is - exact function of these extra trinucleotide repeats not clear.
- mutated gene produces an abnormal protein named _____________.
- selectively produces neural degeneration in ___________________ - it is therefore an _______________________________ disease.
Reminder: Anatomical components of Basal gangliaa. Caudate nucleusb. Putamenc. Globus pallidusd. Ventral lateral nucleus of the thalamuse. Substantia nigra Thalamus
Hypothalamus
Globus
pallidus
Specific defect associated with Huntington’s disease
- medium-sized spiny neurons (containing _____) degenerate in both
- these medium spiny neurons appear to contain the dopamine receptor _____________ preferentially, so that most __ receptors in striatum of Huntington’s patients are lost (see figure on next p age).
- the mechanism of medium spiny neuron cell death is unknown but they have been shown to be more sensitive to _________________ Question. What neurotransmitter is used by neurons projecting onto the caudate and putamen? ________________________________________________________________________________________________________________________________- increased susceptibility to glutamate toxicity might be related to lower levels of a specific subtype of glutamate receptor on medium spiny neurons, the ________________________________________.
Treatment of Huntington’s disease
I. Pharmacological treatments: Several classes of drugs are
employed in an attempt to reduce the symptoms associated with
Huntington’s disease:
1) Involuntary movements: often treated with ___________________.
- these generally involve ___________________________________ - typical antipsychotics : haloperidol (Haldol), sulpiride, - problem with typical antipsychotics is that they produce __________________________________________________ which can exacerbate Huntington’s symptoms, especially at more advanced stages of disease.
- atypical antipsychotics have, by definition, ___________________ __________, but still block D2 receptors.
- effective atypical antipsychotic: Olanzapine.
2) Depressive, aggressive mood: often associated with Huntington’s disease, these mood disorders are treated, accordingly, with ______ ______________________________________________________ ___________________.
- tricyclic antidepressants (especially desipramine) and SSRIs (serotonin -specific reuptake inhibitors) for depressive moods (valproate , fluoxetine [Prozac]).
- irritability and aggression can be treated with antipsychotics with sedative effects (haloperidol ) or adrenergic agents (propranolol ).
Remember, pharmacological treatments _______________________ _________________________________________, but may improve quality of life as disease progresses.
II. Fetal tissue transplant in Huntington’s patients : the results of
two fetal tissue transplant have been recently reported (2001).
- fetal tissue taken from the ________________________________ - implanted in the striatum of Huntington’s patients.
- group in University of Florida reported that 5 of 7 patients improved by 15-20% compared to untreated patients whose disease got worse by an average of 20%/year.
- French group reported similar results in 3 out of 5 implanted patients, showing increased activity in the striatum of implanted patients with concomitant improvement of symptoms.
So far, these studies suggest that fetal tissue transplant _____ _______ _______________________________________________________.
These studies are also very preliminary, and the average patient has had the implant for a few years only. Need to know the ________ __ ________________________________.

Source: http://psych.colorado.edu/~campeaus/2022/Week9reduced.PDF