Segawa syndrome, autosomal recessive

Segawa syndrome, autosomal recessive
Synonyms	N/A
Pronounce	N/A
Specialty	N/A
Symptoms	Dystonia, Parkinsonism, Diurnal variation
Complications	N/A
Onset	Childhood
Duration	Lifelong
Types	N/A
Causes	Genetic mutation in tyrosine hydroxylase
Risks	N/A
Diagnosis	Genetic testing, Clinical evaluation
Differential diagnosis	N/A
Prevention	N/A
Treatment	Levodopa, Dopamine agonists
Medication	N/A
Prognosis	Variable
Frequency	Rare
Deaths	N/A

Segawa syndrome, autosomal recessive is a rare neurological disorder characterized by dystonia and parkinsonism with a notable diurnal variation in symptoms. It is caused by mutations in the gene encoding tyrosine hydroxylase, an enzyme crucial for dopamine synthesis.

Etiology

Segawa syndrome, autosomal recessive, is caused by mutations in the TH gene located on chromosome 11. This gene encodes the enzyme tyrosine hydroxylase, which is responsible for the conversion of tyrosine to L-DOPA, the precursor of dopamine. Deficiency in this enzyme leads to reduced dopamine levels, particularly affecting the nigrostriatal pathway in the brain.

Pathophysiology

The deficiency of tyrosine hydroxylase results in decreased production of dopamine, a critical neurotransmitter in the central nervous system. Dopamine deficiency primarily affects the basal ganglia, leading to the characteristic motor symptoms of dystonia and parkinsonism. The diurnal variation in symptoms is thought to be due to fluctuations in dopamine levels throughout the day.

Clinical Presentation

Patients with Segawa syndrome, autosomal recessive, typically present in early childhood with symptoms of dystonia, which may initially affect the lower limbs, leading to gait disturbances. As the condition progresses, parkinsonian features such as bradykinesia, rigidity, and tremor may develop. A hallmark of the disorder is the diurnal variation in symptoms, with worsening in the evening or after exertion.

Diagnosis

Diagnosis of Segawa syndrome, autosomal recessive, involves a combination of clinical evaluation and genetic testing. The presence of dystonia and parkinsonism with diurnal variation in a child should prompt consideration of this condition. Genetic testing can confirm mutations in the TH gene.

Treatment

The mainstay of treatment for Segawa syndrome, autosomal recessive, is levodopa, which replenishes dopamine levels in the brain. Patients typically respond well to low doses of levodopa, with significant improvement in motor symptoms. Dopamine agonists may also be used as adjunctive therapy. Regular follow-up is necessary to adjust medication dosages and manage any side effects.

Prognosis

The prognosis for individuals with Segawa syndrome, autosomal recessive, varies. With appropriate treatment, many patients experience significant improvement in symptoms and can lead relatively normal lives. However, some may continue to experience residual motor symptoms or develop complications over time.

See also

• Dystonia
• Parkinsonism
• Tyrosine hydroxylase deficiency

External links

• National Institute of Neurological Disorders and Stroke - Dopa-Responsive Dystonia

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WikiMD neurology

External links

• Comprehensive information from the National Institute of health.
  

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