Podcast
Questions and Answers
Which function is primarily associated with dopamine?
Which function is primarily associated with dopamine?
What is a common risk factor for Huntington's disease?
What is a common risk factor for Huntington's disease?
Which treatment aims to reduce dopamine activity in symptomatic management?
Which treatment aims to reduce dopamine activity in symptomatic management?
Which of the following is NOT a function of serotonin?
Which of the following is NOT a function of serotonin?
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Which diagnostic method is NOT included for Huntington's disease?
Which diagnostic method is NOT included for Huntington's disease?
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What is the typical average age of onset for Huntington's Disease?
What is the typical average age of onset for Huntington's Disease?
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Which of the following statements about autosomal dominant inheritance is true?
Which of the following statements about autosomal dominant inheritance is true?
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Which symptom is classified as a cognitive symptom of Huntington's Disease?
Which symptom is classified as a cognitive symptom of Huntington's Disease?
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In the early stages of Huntington's Disease, which symptom is NOT typically observed?
In the early stages of Huntington's Disease, which symptom is NOT typically observed?
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During the middle stage of Huntington's Disease, which ability is lost?
During the middle stage of Huntington's Disease, which ability is lost?
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What is a characteristic feature of chorea in Huntington's Disease?
What is a characteristic feature of chorea in Huntington's Disease?
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Which of the following is a symptom that indicates a person is entering the late stage of Huntington's Disease?
Which of the following is a symptom that indicates a person is entering the late stage of Huntington's Disease?
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What psychiatric symptom is commonly associated with Huntington's Disease?
What psychiatric symptom is commonly associated with Huntington's Disease?
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What is the primary genetic cause of Huntington's disease?
What is the primary genetic cause of Huntington's disease?
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Which symptom is commonly observed in patients with advanced Huntington's disease?
Which symptom is commonly observed in patients with advanced Huntington's disease?
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How does the number of CAG repeats in the huntingtin gene relate to symptom onset?
How does the number of CAG repeats in the huntingtin gene relate to symptom onset?
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Which neurotransmitter levels are abnormal in Huntington's disease due to neuronal cell death?
Which neurotransmitter levels are abnormal in Huntington's disease due to neuronal cell death?
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Which brain regions are primarily affected in Huntington's disease?
Which brain regions are primarily affected in Huntington's disease?
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Which statement accurately describes the progression of speech impairments in Huntington's disease?
Which statement accurately describes the progression of speech impairments in Huntington's disease?
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What aspect of Huntington's disease complicates the recognition and treatment of psychiatric symptoms?
What aspect of Huntington's disease complicates the recognition and treatment of psychiatric symptoms?
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What happens to the levels of huntingtin protein in neurons as Huntington's disease progresses?
What happens to the levels of huntingtin protein in neurons as Huntington's disease progresses?
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Study Notes
Huntington's Disease
- A familial neurodegenerative disorder
- Autosomal dominant inheritance
- Average onset at 40 years old
- No cure
Inheritance
- Genetic trait passed from parent to child
- One mutated gene from one parent can cause the condition
- Child with a parent with the mutated gene has a 50% chance of inheriting it
- Men and women have equal likelihood of having the mutation
- Sons and daughters have equal likelihood of inheriting the mutation
Symptoms (Motor)
- Involuntary twitching
- Excessive restlessness
- Rigidity
- Spasticity
- Decreased coordination
- Voluntary movement abnormalities
Symptoms (Psychiatric)
- Depression
- Aggression
- Irritability
- Apathy
- Impulsivity
- Antisocial behaviour
Symptoms (Cognitive)
- Planning/organising problems
- Memory loss
- Inattention
- Dementia
Chorea
- Brief, involuntary, unpredictable irregular movements
- Flowing from one muscle to the next, like a dance
- Interferes with speech, swallowing, posture, gait
- Disappears in sleep
Stages of HD
Early Stage
- Functional: work, drive, handle money, live independently
- Symptoms: minor involuntary movements, subtle loss of coordination, difficulty with complex thought processes
Middle Stage
- Lose ability to work, drive
- Can perform Activities of Daily Living (ADLs)
- Prominent chorea
- Increasing difficulty with voluntary tasks, problems with swallowing and balance
Late Stage
- Require assistance with all activities
- Often nonverbal
- Bedridden
- Some comprehension may remain
- Severe chorea, rigidity, dystonia, bradykinesia
Speech Impairments
- Slow progression
- Hypophonic/explosive voice
- Impaired articulation
- Decline in voluntary control of lips/tongue/mouth movement
- Worsening speech intelligibility
Cause of HD
- Inherited trinucleotide repeat disorders
- Most common: repeat mutant genes expressed throughout the body (Friedreich's ataxia, Spinocerebellar Ataxia)
Huntington Gene/Protein
- Chromosome 4
- CAG (glutamine residue) repeated up to 30 times
- Codes for the protein Huntington (htt)
- Involved in cellular transport, protein processing, synaptic function
- High expression in brain neurons
How Huntington Gene Causes Neuronal Cell Death
- Unknown mechanisms; proposed mechanisms include:
- Impaired protein trafficking
- Polyglutamine aggregation
- Excitotoxicity
- Oxidative stress
- Programmed cell death (apoptosis)
- Abnormal levels of GABA and dopamine
Symptoms Onset
- Higher the number of CAG repeats, earlier the onset of symptoms
Brain Regions Affected
- Basal ganglia (caudate nucleus, putamen)
- Widespread neuronal loss initially in striatum, extends to other regions
- Accumulation of huntingtin protein
- GABA neurons are lost
Neurotransmitter Pathways Affected
Dopamine
- Functions: reward, pleasure, motor function, compulsion, perseveration
Serotonin
-
Functions: mood, memory processing, sleep, cognition
-
Striatal GABAergic neuron degeneration can cause hyperactivity of dopaminergic systems
-
Reducing dopaminergic activity might help restore neurotransmitter balance
Risk Factors
- Parent with HD mutation has a 50% chance of passing it to their children
Diagnosis
- Physical and neurological exam
- Medical and family history
- Clinical rating scales to assess symptom severity and frequency
- Genetic testing
- Prenatal testing (amniocentesis, chorionic villus sampling)
Treatment
- Symptomatic drug treatment
- Addresses motor symptoms
Future Therapies
- Gene therapy
- Htt aggregation blockers
- Anti-apoptotic drugs
- Antioxidants
- Neurotrophic factors
- Transplantation
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Description
This quiz explores Huntington's disease, a familial neurodegenerative disorder characterized by autosomal dominant inheritance and symptoms affecting motor, psychiatric, and cognitive functions. Understand the genetic implications, typical onset age, and the nature of chorea. Test your knowledge on this significant condition and its impact on individuals and families.
