DYT5: Dopa-responsive dystonia (DRD): management

Evidence-based neurology checklist on dyt5: dopa-responsive dystonia (drd): management: Phenylalanine loading test: protocol Have a low protein breakfast 2 hours before test Administer 100 mg/kg ofL-phenylalanine in 100 mL of water or lemonade. Collect blood samples in lithium heparin bottles at 1…

Phenylalanine loading test: protocol

  • Have a low protein breakfast 2 hours before test
  • Administer 100 mg/kg ofL-phenylalanine in 100 mL of water or lemonade.
  • Collect blood samples in lithium heparin bottles at 1 hour, 2 hours, and 4 hours 
  • Transport the sample on dry ice at -70 degrees Centrigrade
  • Positive result is a high phenylalanine and a low tyrosine level
  • A phenylalanine to tyrosine ratio of >7.5 at 4 hours suggests a DRD syndrome

GCH tests

Imaging

Trial of Levodopa in children

Trial of Levodopa in adults

Synonym

References

  1. Malek N, Fletcher N, Newman E. Diagnosing dopamine-responsive dystonias. Pract Neurol 2015; 15:340-345. 
  2. Segawa M, Nomura Y, Nishiyama N. Autosomal dominant guanosine triphosphate cyclohydrolase I deficiency (Segawa disease). Ann Neurol 2003; 54 (suppl 6):S32-S45.
  3. Lee WW, Jeon BS. Clinical spectrum of dopa-responsive dystonia and related disorders. Curr Neurol Neurosci Rep 2014; 14:461.
  4. Svetel M, Tomić A, Mijajlović M, et al. Transcranial sonography in dopa-responsive dystonia.Eur J Neurol 2017; 24:161-166.
  5. Willemsen MA, Verbeek MM, Kamsteeg E-J, et al. Tyrosine hydroxylase deficiency: a treatable disorder of brain catecholamine biosynthesis. Brain 2010; 133:1810-1822. 

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