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Flashcards in Neurogenetics Deck (14):
1

Duchenne muscular dystrophy:
-inheritance

x-linked recessive
sporadic in 1/3

2

What is duchenne muscular dystrophy?

Muscular dystrophies are a group of inherited conditions with an intrinsic defect of muscle.

They are characterized by progressive wasting and weakness

DMD is where the pelvic/shoulder girdle muscles are affected

3

What are the s/s of duchenne muscular dystrophy?

Delay in motor development
Onset of weakness ~ 3-4 years
pelvic and shoulder girdles
characteristic posture
Calf hypertrophy
Wheelchair bound by 10-12 years
Death from involvement of respiratory and cardiac muscles in 20s

4

What is the genetic mutation is duchenne muscular dystrophy?

dystrophin gene

5

What is the diagnosis of duchenne muscular dystrophy?

developmental delay in boys
muscle weakness
Gower’s sign
toe walking

raised serum creatine kinase (CK)
-CK is a vague marker for muscle disease but in context of other signs/symptoms useful

Electromyography (EMG) – characteristic electrical signs

muscle biopsy – can back up the genetic test

molecular genetic testing
- screen for deletions

6

Describe the carrier testing for duchenne muscular dystrophy

identify mutation in affected boy
test for mutation in female relatives wishing to know carrier status
female carriers of known dystrophin mutations can be offered prenatal testing

7

What is beckers muscular dystrophy?

milder form of duchenne muscular dystrophy:
-Later onset (teens and early twenties)
-Mutation in dystrophin
-Slower progress

8

Huntingdons disease - inheritance?

autosomal dominant chromosome 4

9

What is huntingdons disease

Progressive neurodegenerative disorder
Onset usually between 30 and 50 years

Involuntary movements
Dementia
Progression to severe dependency and deathover 15-20 years

10

What are the early clinical signs of huntingdons disease?

Clumsiness
Agitation
Irritability
Apathy
Anxiety
Disinhibition
Delusions Hallucinations
Abnormal eye movements
Depression

11

What are the late clinical signs of huntingdons disease?

Dystonia
Involuntary movements
Trouble with balance and walking
Trouble with activities that require manual dexterity
Slow voluntary movements
Difficulty initiating movement
Inability to control speed and force of movement
Weight loss
Speech difficulties
Stubbornness

12

What are the end stage clinical signs of huntingdons disease?

Rigidity
Bradykinesia (difficulty initiating and continuing movements)
Severe chorea (less common)
Serious weight loss
Inability to walk
Inability to speak
Swallowing problems, danger of choking
Inability to care for oneself

13

What is the pathogenesis of huntingdons disease?

Condition is characterised by loss of neurons in basal ganglia and especially the caudate nucleus
-caused by more than 36 CAG repeats in the huntingdon gene
-this displays penetrance (as it gets passed down, the younger those are affected)

14

What gene is implicated in genetic alzheimers?

-ApoE
-ApoE 4 predisposes to alzheimers
-ApoE 2 is assoc. with longevity