Genetic Diseases Flashcards
what is the pattern of inheritance in Duchenne muscular dystrophy?
X-linked recessive
only affects males
what does Duchenne muscular dystrophy cause?
a delay in motor development
when does weakness come on in Duchenne muscular dystrophy?
around 3-4 years of age
what muscles are affected by weakness in Duchenne muscular dystrophy?
pelvic and shoulder girdles
when does death occur in Duchenne muscular dystrophy and why?
usually in 20s
due to weakness of respiratory and cardiac muscles
what causes Duchenne muscular dystrophy?
dystrophin mutation on the X chromosome
what does dystrophin code for and what does disruption cause?
dystrophin protein which connects proteins
loss of muscle cells
what are the two main types of dystrophin mutations?
large deletions
point mutations, small insertions and deletions
what are some signs of muscle weakness in Duchenne muscular dystrophy?
Gower’s sign
toe walking
exaggerated lumbar lordosis
what is Gower’s sign?
when the arms are used to compensate for the weakness of the pelvic girdle when getting up from the floor
what sign of Duchenne muscular dystrophy is seen in the legs?
calf hypertrophy
muscles appear large but are very weak
what blood is high in Duchenne muscular dystrophy?
serum CK
what tests can be done to diagnose Duchenne muscular dystrophy?
serum CK
genetic testing
EMG
muscle biopsy
when is the onset of Huntington’s disease?
usually 30-50
how is Huntington’s disease inherited?
autosomal dominant pattern
