Lecture 12: Motor 2: Huntington: Chapter 22 Flashcards
What is the prevalence of huntington disease? Are there differences in western vs. non-western countries? What could be an explanation?
0,6-13,7 individuals per 100.000 in western
Only 1-7 individuals per 1.000.000 in non-western
Apparently it’s related to the European genetics
What does it mean that huntington is autosomal dominant inherited?
This means if 1 parent has huntington, you will have 50% chance of inheriting it and developing huntington
What is huntington’s disease?
A hereditary neurodegenerative brain disease that is characterized by progressive motor impairments, cognitive decline and mood/behavior changes
When is the typical onset of Huntington’s? And what is the duration?
Between 30-50
Duration: 15-20 years
How does Huntington disease look in the DNA?
Repeated sequences of CAG
- More than 36 repeats indicates huntington’s
- The number of repeats indicates severity/course
How can Huntington’s disease start?
When your parents don’t have it, but you have an unlucky 27-35 repeats of CAG, you can be the first in your family
What is a premanifest mutation carrier?
An individual that carries the gene, but motor impairments are absent. Often cognitive impairments are there and later motor impairments will come
What is huntingtin? What is its function?
The protein that is made by the gene involved in Huntington’s.
Function: nervous system development and cell adhesion
What is toxic gain-of-function disease?
If a mutation occurs, the proteins gain a new function and does something it didn’t do before
What happens in translation of genes in Huntington disease?
Proteins clump together, which make it hard to read DNA in the cell. So it interrupts communication
Where does the first and most severe neurodegeneration occur in the brain? What is the function of this area?
In striatum (caudate nucleus and putamen)
Function: coordinating movements
Degeneration in which brain areas explain motor issues, cognition issues and psychiatric symptoms in Huntington’s?
Motor: striatum
Cognition: loss of neurons/thinning in cortex and white matter
Psychiatric: dopaminergic system
What is the consequence of striatal degeneration? (3)
- Involuntary movements
- Tremors
- Poor coordination
What age is the median onset of motor issues in HD?
Age 45 (change from prodromal into clinical phase)
What are some prodromal issues in HD?
Lower functionability, some cognitive impairment. Motor functions intact
Why do people with HD die from the disease?
Motor complications, such as not being able to swallow anymore
What are 3 motor symptoms in HD?
- Involuntary movements
- No rhythmic or repetitive movements/almost dance-like
- Difficulty walking
What are 4 key cognitive symptoms of HD?
- Attention
- Mental flexibility
- Planning
- Emotion regulation
Late stages of HD are similar to…
Alzheimer’s disease
What were the results of the TRACK-HD study aimed on identifying the earliest detectable changes in HD?
Early cognitive deterioration, especially in cognitive tests that had a motor or psychomotor component (such as stroop word-reading test)
What percentage of HD patients suffer from depression and how can you explain this?
50% –> difficult to live with such a disease