AXIS I
1. AGE AT ONSET

Dystonia may emerge at any age, and age at onset is an important consideration for the clinical presentation and the prognosis. For example, dystonia of childhood onset is likely to have a genetic cause, and is more likely to progress from focal to generalized.

• Infancy (Birth to 2 years): Inherited metabolic disorders commonly present at this age: dystonic syndromes due to abnormalities of dopamine synthesis are found, such as mutations in the tyrosine hydroxylase or sepiapterin reductase genes.
   
• Childhood (3–12 years): Most metabolic disorders presents in childhood or infancy. In addition, early childhood onset may be consistent with dystonic cerebral palsy. Of importance are genetic forms of dystonia, in particular, DYT-TOR1A and DYT-PARK-GCH1 (previously termed DYT 1 and DYT5 respectively), and other generalized dystonias.
   
• Adolescence (13–20 years): DYT-PARK-GCH1, Wilson’s disease, other generalized dystonias.
   
• Early adulthood (21–40 years): median age for development of DYT-THAP1 (previously termed DYT6) dystonia is 28 years. Wilson’s disease remains a consideration.
   
• Late adulthood (>40 years): Sporadic focal dystonia.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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