Flashcards in DNA & Neuro Disorders Deck (45)
2 kinds of neurodegen conditions?
subset of inherited neurodegen conditions caused by?
unstable repeat expansions
what is the most common type of repeat expansion?
there is also tetranucleotide
below the threshold for number of repeat expansions?
stable in both sperm/egg and somatic
above the threshold for number of repeat expansions?
unstable and could become toxic
what is a characteristic of unstable repeat expansions?
what is it called when the expansion size increases across generations?
anticipation of repeat expansions associated with?
greater severity of symptoms
what is a proposed mechanism for expansion?
what is anticipation in terms of unstable repeat expansions for neuro degen diseases?
the expansion size increases across generations
unstable repeat expansions are usually what kind of disorders generally?
3 kinds of unstable repeat expansion in terms of coding?
1. non-coding = loss protein function
2. non coding = novel RNA
3. codon = novel toxic protein
Huntington's mutation is where in terms of coding?
repeats in codon
Friedreich ataxia mutation happens in which coding area?
non-coding leads to loss of protein function
what do you see in late onset unstable repeat expansion?
loss of movement control
3 main features of Huntingtons:
1. motor disorder
2. cognitive disorder
3. psychiatric/emo disorder
Huntington's early or late onset?
small proportion can be <20 due to expansion
huntington's inheritred how genetically?
What repeat in huntington's?
CAG repeat in HTT gene
What is HTT?
protein called huntingtin
expanded CAG in huntingtin has toxic effect where in brain?
esp. medium spiny neurons
what do you see in brain scans of huntington's?
PolyQ-huntingtin cleaved by capsases and make what toxic fragments?
huntington's you lose function of normal HTT and also?
huntington's 27-35 repeats is?
huntington's >40 repeats?
huntington's zone of reduced penetrance is how many?
huntington's less than 26 repeats?
CAG repeats mitigated by?