13a: Trinucleotide Repeats Flashcards Preview

Neuroscience > 13a: Trinucleotide Repeats > Flashcards

Flashcards in 13a: Trinucleotide Repeats Deck (29):
1

One hypothesis on how trinucleotide repeat expansions occur is related to (X) during which process?

X = Backward slippage of DNA Pol

DNA replication

2

Trinucleotide repeat expansions (increase/decrease/don't change) in size with each successive generation of patients.

Increase

3

The molecular connection between growing number of trinucleotide repeats and increase in severity of disease phenotype.

Anticipation

4

Often, increase in severity of disease manifests as:

Younger age of onset

5

T/F: All diseases that arise by mechanism of tri-NT repeat expansion exhibit anticipation.

True

6

In Huntington's Disease, where in gene do the tri-NT repeat expansions occur?

Within exons

7

The expansion in HD results in (increase/decrease) size of (X) tract in (Y) protein.

Increase;
X = glutamine
Y = huntingtin

8

The mutated version of huntingtin protein (breaks down/aggregates).

Aggregates

9

Most characteristic result/symptom of neuronal degeneration of HD.

Increased involuntary muscle movements

10

In Fragile X syndrome, where in gene do the tri-NT repeat expansions occur?

Promoter region

11

Which tri-NT repeat is implicated in Fragile X syndrome? In which gene?

CGG repeat in FMR1 gene

12

In (X), the tri-NT repeat expansion in the promoter region cause (Y) and silencing of the (Z) gene.

X = Fragile X syndrome
Y = methylation of CpG islands
Z = FMR1

13

HD is (dominant/recessive) defect with (gain/loss) of function.

Dominant; gain

14

Fragile X is (dominant/recessive) defect with (gain/loss) of function.

Recessive; loss

15

(Males/females) more vulnerable to Fragile X syndrome.

Males (only 1 X chromosome)

16

Friedreich's Ataxia involves (X) tri-NT repeat expansion in which region of (Y) gene?

X = GAA
Intron;
Y = FRDA1 (frataxin)

17

Key symptoms of Friedreich's Ataxia.

Loss of voluntary movement and enlarged hearts

18

Myotonic dystrophy is associated with expansion of (X) tri-NT repeat in (Y) region of (Z) gene.

X = CTG
Y = 3' untranslated region (UTR)
Z = DMPK

19

The 3' UTR begins just (before/after) stop codon.

After

20

An expansion in 3' UTR region compromises which characteristic of the (X) molecule?

X = mRNA

Stability

21

Myotonic dystrophy is (dominant/recessive) defect with (gain/loss) of function.

Dominant; gain

22

The 5' UTR of gene is also known as:

The promoter region

23

T/F: It's possible to predict the precise age of onset of HD based on number of CAG repeats.

False - only approximation

24

Diseases that result from expansions in (X) regions of gene cannot be amplified by PCR because the expansions are too (Y).

X = non-coding;
Y = large

25

An alternative technique used to detect large-scale tri-NT expansions is (X), where (DNA/mRNA) is processed/analyzed in which ways?

X = Southern blotting
Genomic DNA;

Digested by restriction enzymes and run on a gel

26

Since in (X) technique the DNA appears as smear on the gel, it's necessary to subsequently use probe that's labeled with (identical/complementary) sequence.

X = southern blotting;
Complementary

27

T/F: Southern blotting incapable of detecting methylation status of gene.

False

28

To detect methylation status of gene, the (DNA/mRNA) must be digested by enzyme that specifically:

DNA;
Digests unmethylated regions

29

The pre-mutation allele of Fragile X has which phenotype, if any?

Development of Fragile X associated tremor/ataxia (FXTAS)