DNA Testing: Neurodegenerative Disorders Flashcards Preview

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Flashcards in DNA Testing: Neurodegenerative Disorders Deck (21):
1

What are unstable repeat expansions? what are the most common?

Repetitions of >3 nucleotides in tandem
Trinucleotides Repeats

2

How is it possible for people with fragile X syndrome to develop symptoms when they have a healthy # of repeats?

Because the mRNA gains toxic properties

3

Define: Anticipation

Expansion of repeats in the following generations

4

How is the process of expansion thought to occur?

because during replication of the DNA one of the repeats comes off the template strand and other downstream attaches to that site and then normal replication continues to occur

5

What inheritance pattern shows Huntington's Disease

Autosomal Dominant

6

Huntington's Disease age of presentation

Adult

7

at the beggining of the pathology of Huntington's Disease there is increased movement that progressively disappears T/F

T

8

Where is the repeat found in Huntington's Disease?
what is the name of the gene?
What does the repeat code for?

CAG repeat in exon 1 of the
gene hungtintin in chromosome 4
Poly-glutamine tail (PolyQ)

9

what cells are affected for the motor changes seen in Huntington's Disease

Medium Spiny Neurons of the basal Ganglia

10

why is the polyQ tail of the gene problematic if too long

can induce apoptosis due to deficient cleaving by caspases that produce N terminals that can aggregate into plaques (more oxidative stress and excitotoxicity)

11

What are the gene categories found in Huntington's Disease?

Normal (40)

12

What inheritance pattern shows Spinocerebellar ataxias

Autosomal Dominant (late onset)

13

In Spinocerebellar ataxia SC A6 what is the damaged protein

Ca+2 Channel

14

in SCA6 where is the gene located and how many repeats required to get the condition

19

15

In Fredreich Ataxia what is the inheritance pattern

Autosomal Recessive

16

In Fredreich Ataxia when is the onset

puberty

17

Fredreich Ataxia symptoms and signs

Progressive limb ataxia, cardiomyopathy, diabetes mellitus

18

In Fredreich Ataxia where is the repeat located
What is the name of the gene? what is its function?

In an intron
FXN located in chromosome 9 (ion exchanger in mitochondria)

19

In Fredreich Ataxia how many repeats required for developing symptoms

66-1700
Repeats form triple helix that inhibits transcription of the gene (GAA)
Symptoms can also be developed by inactivating point mutations

20

Is genetic testing of children recommended?

No as there is nothing to be done

21

Wat is the role of the protein hungtintin?

transcription factor for other genes