MS and the leukodystrophies Flashcards
What are leukodystrophies?
Diseases relating to white matter.
Which diseases can mutations in the PLP1 gene cause?
Pelizaeus Merzbacher disease and spastic paraplegia type 2
Which chromosome is the PLP1 gene on?
X chromosome.
What are the most common types of mutations in the PLP1 gene?
Duplications.
What does dysmyelination mean?
Myelin never formed.
What does demyelination mean?
Myelin formed and it breaks.
What are the symptoms of Pelizaeus Merzbacher disease?
Impaired motor development Nystagmus (abnormal eye movements) Ataxia Choreoathetosis (abnormal movements of upper limbs) Cognitive impairment.
What causes pelizaeus merzbacher disease?
Widespread hypomyelination of CNS.
What are spastic paraplegias characterised by?
Degeneration of distal ends of long spinal cord axons.
What do pyramidal neurons do?
Pyramidal neurons are a type of neuron found in areas of the brain including the cerebral cortex, the hippocampus, and the amygdala. Pyramidal neurons are the primary excitation units of the mammalian prefrontal cortex and the corticospinal tract.
Which transgenic animals have been made for Pelizaeus Merzbacher disease?
Plp1 gene knockout mice
Plp1 overexpressing mice and rats.
What happened in the plp1 knockout mouse?
Subtle abnormalities only.
Oligodendrocyte numbers are normal.
Neurological signs >15 months.
Develop a late onset axonal pathology
- axonal swellings, small diamater axons
- distal degeneration of long spinal axons.
What is the age of onset in X-ALD?
Childhood and adolescent onset.
What is the pathophysiology of X-ALD?
Adrenal atrophy
Extensive demyelination
Perivascular accumulation of lymphocytes and plasma cells in the CNS
Accumulation of very long chain fatty acids in adrenal cortical cells and microglia.
Markedly shortened lifespan.
What does AMN stand for?
Adrenomyeloneuropathy
What is the mode of inheritance of AMN?
X-linked recessive
What happens in AMN?
Neuropathological changes confined to spinal cord and peripheral nerves.
Begins with stiffness or clumsiness and legs and gait disturbances progress slowly over years.
Urinary disturbance and sexual dysfunction.
Neuropsychologic function is normal or minimally impaired.
What does ALD stand for?
Adrenoleukodystrophy