Genetic principles through neurodegenerative disease

Question 1

CAG repeat length unaffected HD

Answer 1

10-26

Question 2

CAG repeat length intermediate unaffected HD

Answer 2

27-35

Question 3

Reduced penetrance HD

Answer 3

36-39

Question 4

CAg repeat length full penetrance HD

Answer 4

40+

Question 5

Age of onset of HD

Answer 5

35-44

Question 6

Inheritance pattern HD

Answer 6

Autosomal dominant with anticipation

Question 7

What is anticipation

Answer 7

decreasing age of onset and increasing severity of sx is observed in successive generations

Question 8

CAG repeats for juvenile HD

Answer 8

> 60

Question 9

Duration of HD before death

Answer 9

15-18 years

Question 10

Testing for HD

Answer 10

Fluorescent PCR

Question 11

Presymptomatic testing

Answer 11

not currently affected, wants to know if he will be in future

Question 12

Pre-implantation testing

Answer 12

Embryos created and tested before implanting

Question 13

Prenatal testing

Answer 13

Amniocentesis/CVS for trinucleotide expansion

Question 14

Mild myotonic dystrophy

Answer 14

50-150 repeats

Cataracts, myotonia (can’t relax clenched hands)

Question 15

Classic myotonic dystrophy

Answer 15

100-1000 repeats

Progressive muscle weakness and wasting, myotonia, cataracts, cardiac abnormalities

Question 16

Congenital myotonic dystrophy (>1000 repeats)

Answer 16

AT birth

Hypotonia, muscle weakness, swallowing difficulties

Question 17

Inheritance pattern of myotonic dystrophy

Answer 17

Autosomal dominant

CTG triplet repeat in the 3’ non-coding region of DMPK

Question 18

Symptoms of myotonic dystrophy

Answer 18

Swallowing, weaknesses breathing weakness, cataracts, heart difficulties