Lecture 5 - Unstable Repeat Expansions pt 1

Question 1

what are the 4 trinucleotide repeat expansion diseases mentioned in FA?

Answer 1

HD, Friedreich Ataxia, Myotonic dystrophy, Fragile X

Question 2

repeat expansion disorders often show _____. this is where the disease severity ___ and the age of onset ____ with successive generations.

Answer 2

anticipation;
increases;
decreases

Question 3

Fragile X:
____ ____ inheritance.
what is the repeat?
what is the gene?

Answer 3

X-linked dominant;
CGG;
FMR1 (in exon 1)

Question 4

Fragile X:

repeat is the in the (5 or 3 prime) (translated or untranslated region?

Answer 4

5’ untranslated

Question 5

fragile X:

greater than ____ repeats causes ____ ____ and the gene is ____

Answer 5

200;
promoter methylation;
not transcribed

Question 6

normal people have less than ____ CCG repeats. premutation alleles = transcribed or no?
can they expand in future generations? what is that called?

Answer 6

45;
transcribed;
can expand–called unstable

Question 7

fragile x symtpoms:
mental retardation, esp in ____;
large ___, large ____, large and ____ ears

Answer 7

males;

testes, jaw, everted

Question 8

_____ recognizes the methylgroups on CGG’s and turns off the promoter. in additions, the histones are ____

Answer 8

MeCP2;

de-acetylated

Question 9

FMR1 protein is thought to be involved with the metabolism and transport of ____

Answer 9

RNA

Question 10

large FMR1 expansions to full mutations are usually not seen through ____; ie no ___ to _____ transmission

Answer 10

fathers;

father to daughter

Question 11

fragile x: larger premutation alleles are more or less likely to expand?

interrupted repeats = more or less likely to expand?

Answer 11

more, less

Question 12

premutation carrier females are at an increased risk of ____ and early menopause.

older premutation males may develop ____

Answer 12

premature ovarian female;

FXTAS = fragile X associated tremor/ataxia syndrome

Question 13

of PCR and southern blotting, which can detect the large disease causing expansions in fragile X?

which is useful for determining the size of normal alleles?

Answer 13

southern blotting, PCR

Question 14

look at ppt for restriction enzyme things

Answer 14

k