Neurogenetics Flashcards
What mode of inheritance does duchenne muscular dystrophy have?
X-linked recessive
At what age does Duchenne muscular dystrophy present?
3-4
How does Duchenne muscular dystrophy present?
Delay in motor development
Pelvic and shoulder girdle weakness
How does Duchenne muscular dystrophy progress?
Presentation at age 3-4
Wheelchair bound by 10
Death in 20s
What causes death in DMD?
Involvement of cardiac and respiratory muscles
What is the characteristic posture of a child with DMD?
What is the pathogenesis of DMD?
Mutation in the dystrophin gene on chromosome X which codes for dystrophin protein
What is dystrophin?
Dystrophin is an important component within muscle tissuethat provides structural stability to the dystroglycan complex (DGC) of the cell membrane
What is Gower’s sign?
Gowers’ sign is a medical sign that indicates weakness of the proximal muscles, namely those of the lower limb
The patient that has to use their hands and arms to “walk” up their own body from a squatting position due to lack of hip and thigh muscle strength
What signs might be seen in DMD?
Gowers sign
Calf hypertrophy
Toe walking
Difficulty climbing stairs or rising from sitting
In what proportion of boys affected by DMD is this due to new mutations?
1/3
What mode of inheritance does Huntington’s disease have?
Autosomal dominant
At what age does Huntington’s disease usually present?
30-50
What is the life expectancy after the onset of Huntington’s disease?
15-20 years
What are the early clinical signs of Huntington’s disease?
Clumsiness
Agitation
Irritability
Apathy
Anxiety
Disinhibition
Delusions Hallucinations
Abnormal eye movements
Depression
What are the later clinical signs of Huntington’s disease?
Dystonia
Involuntary movements
Trouble with balance and walking/inability to walk
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/inability to talk
Stubbornness
Rigidity
Bradykinesia
Severe chorea
Swallowing problems, danger of choking
What is the pathology associated with Huntington’s disease?
Caudate atrophy
What is the molecular genetic defect in Huntington’s disease?
Abnormal CAG production on the Huntingtin gene
Reaches 36 repetitions to cause Huntingtons disease
What does CAG code for?
Glutamine
