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Implantation of Osmotic Pumps and Induction of Stress to Establish a Symptomatic, Pharmacological Mouse Model for DYT/PARK-ATP1A3 Dystonia
Published on: September 12, 2020
Hereditary progressive dystonia with marked diurnal fluctuation
1Segawa Neurological Clinic for Children, Chiyoda-ku, Tokyo, Japan. segawa@segawa-clinic.jp
Brain & Development
|November 25, 2010
Summary
Segawa disease, a form of hereditary progressive dystonia, results from GCH-1 gene mutations causing dopamine deficiency. Levodopa treatment is effective regardless of illness duration.
Area of Science:
- Neurogenetics
- Movement Disorders
- Biochemistry
Background:
- Hereditary progressive dystonia with marked diurnal fluctuation (HPD), now known as autosomal dominant GTP cyclohydrolase 1 deficiency or Segawa disease, is caused by GCH-1 gene mutations.
- This deficiency leads to reduced tetrahydrobiopterin, impacting tyrosine hydroxylase (TH) activity and dopamine levels in specific neuronal pathways.
Purpose of the Study:
- To elucidate the pathophysiology of Segawa disease.
- To correlate genotype with the age-dependent clinical manifestations.
- To understand the therapeutic response to levodopa.
Main Methods:
- Analysis of GCH-1 gene mutations.
- Assessment of TH activity and dopamine levels in affected neuronal pathways.
- Clinical evaluation of age-dependent symptoms and diurnal fluctuations.
- Evaluation of levodopa treatment efficacy.
Main Results:
- GCH-1 mutations cause partial tetrahydrobiopterin deficiency, selectively reducing TH activity in nigrostriatal dopamine (NS DA) neurons.
- Age-dependent symptoms include failure in dopamine neuron morphogenesis (infancy), postural dystonia (childhood), action dystonia and tremor (later childhood/adulthood), and growth stagnation.
- Diurnal fluctuations are prominent in childhood and decrease with age.
- Levodopa demonstrates consistent efficacy, irrespective of disease duration, as no degenerative changes occur.
Conclusions:
- Segawa disease results from impaired dopamine synthesis due to GCH-1 mutations.
- The specific mutation locus influences the presence of action dystonia.
- Levodopa effectively manages symptoms by replenishing dopamine levels.
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