Dystrophin-Glycoprotein Complex
Which muscle type is not striated
Smooth
Skeletal
Cardiac
Where would you find Dystrophin
Outside cell, connected to ECM
Inside cell, connected to F-actin
How does disrupted DGC lead to cell death?
Perturbed cell membrane
Transient local membrane disruptions -> Ca efflux
Transient local membrane disruptions -> Ca influx
Activation of proteases
Increased DGC signalling
Disrupted DGC signalling
What condition does caveolin 3 mutation cause?
L-G MD
Becker MD
DCM
What type of cardiomyopathy does sarcoglycan mutation cause?
DCM
HCM
Which of these are features of HCM
Hyper-contractile systolic function
Hyper-relaxation diastolic function
Poor relaxation
Poor contractile force
Which of these are associated with HCM
Palpitations
Dizziness
Sudden Death
Obesity
No symptoms
Tachycardia
What is the mode of inheritance for HCM
Autosomal dominant
Autosomal recessive
X-linked recessive
In which ventricles would you expect hypertrophy
Left
Right
Left and right
Left with or without right
Choose 2 other features of HCM
Myofibril disarray
Interstitial fibrosis
Aneurysms
Unilateral headaches
Consistent prognosis in all patients
Which of these are genes that may cause HCM?
TNNT2 -> troponin T
TNNC1 -> troponin C
TPM1 -> alpha tropomyosin
TTN -> titin
MHY7 -> beta myosin heavy chain
What are the consequences of MHY7 mutations
Disruption to mechanical properties
Disruption to catalytical properties
Reduced force generation
Does the heart enlarge in DCM
No - the walls are only thin
Yes - the walls are thin and stretched
Which of these are co-morbidities for DCM
Skeletal myopathy
Sensorineural deafness
Conduction-system disease
Migraine
Hyperuricaemia
Which of these describes DCM
Inherited
Sporadic
Both
Which of these describes dystrophin?
X-linked
Autosomal
What is the most common site for dystrophin mutation?
Rod domain
NH2 terminal
Cysteine-rich domain
Carboxyl terminal domain
Which of these are true for the central rod domain of dystrophin
23 spectrin-like repeats
24 spectrin-like repeats
B pleated sheet
Alpha helix
Hinge regions to bind actin
Hinge regions to allow movement during contraction
Binds actin
Does not bind actin
DMD is...
X-linked
Sporadic
Autosomal dominant
DMD is worse in..
Upper limbs
Lower limbs
Why is BMD less severe than DMD
DGC is fully functional
DGC is partially functional
Which of these diagnosis years is true?
DMD = 3-5 years, BMD = 12 years
DMD = 12 years, BMD = 3-5 years
Which of these might be shown by BMD histology
Fibre degeneration
Centres of regeneration
Necrosis
Adipocyte deposition
Amyloid beta plaques
Is DCM seen in all MD
Yes
No
LG MD 2E is a mutation in a gene coding for...
Dystrophin
Dystroglycan alpha
Alpha sarcoglycan
Beta sarcoglycan
Autosomal Dominant Emery Dreifuss MD cause?
Mutated LMNA gene -> lamin A and C
Mutated LMNA gene -> lamin A and B
Is AD ED MD associated with DCM
Yes - 35% have it by middle age
No
Yes - 100% have it by middle age
What is a common cause of death in AD ED MD
AV fibrilation
Ventricular dysrhythmias
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