Besides classification by affected body parts
and by genetics, dystonias can be also classified based on the age of onset.
Early-onset primary dystonia (DYT1, TOR1A gene, autosomal dominant inheritance)
typically presents in childhood or adolescence and only on occasion in
adulthood. Among other form of dystonia for which the gene has been identified,
DYT5 (autosomal dominant Segawa syndrome, caused by mutation in GCH1) shows a
variable age of onset, but frequently begins in childhood, as well as DYT11
(myoclonic dystonia, autosomal dominant, caused by mutation in the SGCE gene).
Also DYT8 (or paroxysmal nonkinesigenic dyskinesia, caused by mutation in MR1)
and DYT12 (rapid onset dystonia-parkinsonism, ATP1A3 gene) can begin at all
ages. Finally, ACTB mutations have been reported in two twins affected by a
form of juvenile onset dystonia.
References:
Németh et al, 2002, PMID: 11912106
