Lexture 20 Flashcards
What is the cause of down syndrome?
Inheritance of an extra twenty first chromosome
What is congential?
A disorder that one is born with
What is downsyndrome? Hereditary or congenital?
congenital
What is down syndrome chracterized by?
Moderate to severe intellectual disability and often physical abnornamlities
What happens to people with down syndrome’s brain?
It degenerates in a manner similar to Alzheimers
What is an autoimmune demyelinating disease that usually occurs in people’s late twenties or thirties?
Multiple Sclerosis
What is a sporadic disease?
One that is not obviously caused by inherited gene mutation or an infectious agent
What type of disease is MS?
Sporadic
What happens with MS?
At scattered locations within the central nervous system, myelin sheaths are attacked by the person’s own immune system, leaving behind hard patches of debris called scelortic plaques
What happens in MS people in regards of neural transmission of neural messages?
The transmission of neural messages through demyelinated axons is interrupted
What happens with symptoms of multiple sclerosis? What’s this called?
They go through cycles where they flare up and then decrease after varying periods of time.
Remitting-relapsing MS
What is the pattern of remitting-relapsing MS followed by?
Progressive MS
What is progressive MS charcterized by?
A slow continuous increase in symptoms
Is there yet an effective treatment for MS?
No
What drugs have been found to help MS that can help a little? What are they?
Intereron: a protein that modulates immune system activity
Glatiramer acetate: peptide that mimic myelin (decoy approach)
What people are more likely to get MS? Why?
People who spend their childhood in places far from equator.
It is likely that some disease contracted during childhood spent in region in which virus is prevalent causes person’s immune system to attack his or her own myelin
What is degeneration typically the result of?
Apoptosis
What is apoptosis triggered by?
By collections (aggregates) of misfolded proteins that disrupt normal cellular function
Whats transmissible spongiform encephalopathy?
A contagious brain disease whose degenerative process gives the brain a sponge like appearance
What does transmissible spongeform encephalopathy include?
mad cow disease
What is the accumulation of misfolded prion protein responsible for?
Transmissible spongiform encephalopathies
What are prions?
Misfolded proteins with the ability to transmit their misfolded shape onto normal variants of the same proteins
What happens when a misfolded prion protein interacts with a correctly folded prior protein?
It will cause them to misfold as well
How do prior proteins diseases spread?
From cell to cell and animal to animal by means of contact with misfolded prion protein
What is special about prion protein diseases?
It is the only infectious agent that is just a protein
What do other infectious agents (besides prion proteins) contain?
Nucleic acids
What is huntington’s disease caused by?
A dominant mutation in the huntingtin gene, overtime aggreagtes of huntingtin protein form in the basal ganglia, causing neurodegeneration.
How many people does huntington disease affect?
1 in 10000
At what age do symptoms of huntingtons disease begin?
Death?
Between 30 and 50 years of age.
15-20 years later
What is huntingtons disease chracterized by?
severe lack of coordination, uncontrallable jerky limb movemnts and eventually dementia followed by death
Where is the huntingtin protein heavily expressed?
In the input nuclei of the basal ganglia
What do mutated huntingtin proteins tend to do?
What happens?
Aggregate.
Causes degeneration of neurons in these regions
Is there any cure or treatment for huntingtons?
no
How can antisense DNA or RNA be adminstered
intrathecally (in the spinal cord)
What is another degenerative movemnt disorder?
Parkinsons
What is parkinsons associated with?
Degeneration of dopamine neurons in the midbrain - specifically in the substantia nigra
How much of the population does parkinson’s affect?
1%
When do symptoms of parkinsons appear?
Afer the age of 60
What is parkinson’s charcterized by?
Shaking, muscular rigidity, slowness of movement, difficulty walking and eventually dementia
What happens when people with parkinsons go without treatment?
They have increasing difficulty initiating purposeful movement
What are the causes of parkinson’s disease
Largely unknown
What do the death of midbrain dopamine neurons seem to relate to?
The aggregation of the protein alpha-synuclein
What does the protein alpha synuclein, which is heavily expressed in dopamine neurons tend to do?
What does this cause?
They tend to aggregate
These protein aggregates cauuse dopamine neurons to undergo apoptosis overtime
What does reduced dopamine signaling in the basal ganglia disrupt?
is there a cure?
Movement.
No
What else also develop in parkinsons?
Are there good treatments?
Cognitive, emotional and sleep disturbance.
No
What is a protein that is heavily expressed in midbrain dopamine neurons?
Alpha synuclien
What is the function of alpha-synuclein?
Not clear