Inherited Diseases of Skeletal Muscle Flashcards
When will Muscular Dystrophies present?
Near Adulthood
– NOT IN INFANCY
Muscular Dystrophies involve progressive muscle damage near adulthood. They will NOT present when?
NOT present in infancy
What are 2 X-linked Muscular Dystrophies?
- Duchenne
2. Becker
What gene is mutation and where with X-linked Muscular Dystrophies?
DMD gene – Xp21 chromosome
What protein is absent or decreased with X-linked Muscular Dystrophies?
Dystrophin
Can female carries of X-linked muscular dystrophies be affected?
May be mildly symptomatic
Level of Dystrophin protein with Duchenne Muscular Dystrophy?
ABSENT
When will symptoms present with Duchenne muscular dystrophy and what is the outlook?
Symptoms around 5 yo
– Death at 25-30 yo
What are the symptoms of Duchenne?
Muscle weakness and clumsiness
Besides muscles, what other impairments will be seen with Duchenne?
Heart and cognitive impairments
– Dystrophin protein is absent from heart and CNS too
Level of Dystrophin protein with Becker muscular dystrophy?
DECRASED
When will symptoms present and what is the outlook for Becker muscular dystrophy?
Symptoms at late childhood
– NORMAL LIFE SPAN
Does Becker muscular dystrophy also have cardiac disease like Duchenne?
Yes
What histo change of the muscles will be present with Duchenne and Becker x-linked muscular dystrophies?
Pseudohypertrophy
=> increased collagen and fat
What histo change of the muscles will be present with Duchenne and Becker Muscular Dystrophies?
Pseudohypertophy
=> increased collagen and fat
What are the 2 X-linked Muscular Dystrophies, what gene and protein are mutated/absent/decreased?
** DMD gene on Xp21 mutated
Duchenne - ABSENT Dystrophin
Becker - DECREASED Dystrophin
Limb-Girdle Muscular Dystrophy has forms that are inherited how?
AD and AR forms
What is the symptom of Limb-Girdle Muscular Dystrophy?
Proximal muscle weakness
How is Myotonic Dystrophy inherited?
AD
What trinucleotide repeat is seen with Myotonic Dystrophy?
CTG repeats
What protein/gene is mutated with Myotonic Dystrophy?
DMPK
What histo change will be present with Myotonic Dystrophy?
Ring fiber
What are the general symptoms (4) of Myotonic Dystrophy?
Weakness
Cataracts
Endocrinopathy
Cardiomyopathy
What are the general symptoms (4) with Myotonic Dystrophy?
Weakness
Cataracts
Endocrinopathy
Cardiomyopathy
What specific muscle weakness symptom will present with Myotonic Dystrophy?
Stiffness – difficulty releasing grip
Ptosis and “hatchet face” can present with?
Myotonic Dystrophy
Diseases of lipid or glycogen metabolism can also cause myopathies. What are 3?
Carnitine Polmitoyltransferase 2 deficiency
McArdle Disease
Pompe Disease
Symptoms of Carnitine Palmitoyltransferase 2 deficiency?
Episodic muscle damage with exercise and fasting
McArdle Diseases involves _____ deficiency
Myophosphorylase deficiency
Symptoms of McArdle Disease?
Episodic muscle damage with exercise
Pompe Disease involves _____ deficiency
Acid Maltase deficiency
Symptoms of Pompe Disease?
Glycogenesis of infancy
How is mitochondrial DNA inherited?
Maternal inheritance
With Mitochondrial Myopathies, what is impaired?
Ability to generate ATP is impaired
What histo change will be seen with Mitochondrial Myopathies?
Ragged Red Fibers
What are the general symptoms of Mitochondrial Myopathies?
Weakness, Rhabdomyolysis (increased creatine Kinase)
What will be increased in the serum with Mitochondrial myopathies?
Serum Creatine Kinase
What specific weakness is seen with Mitochondrial myopathies?
EOM weakness
= Chronic progressive External Ophthalmoplegia
