ABSTRACT
Currently, at least 12 types of dystonia can be distinguished on a genetic basis.
Advances in the molecular genetics of dystonia have led to the recent identification
of a 3-bp deletion in the DYT1 gene, causing early-onset generalized torsion dystonia
(TD), and to the detection of mutations in the GTP cyclohydrolase I and the tyrosine
hydroxylase genes causing dopa-responsive dystonia (DYT5). A missense change in the
D2 dopamine receptor has been shown to be associated with myoclonus-dystonia in one
family. In addition, six other dystonia gene loci have been mapped to chromosomal
regions, including a locus for a mixed dystonia phenotype (DYT6), one form of focal
dystonia (DYT7), two types of paroxysmal dystonia (DYT8, DYT9), X-linked dystonia-parkinsonism
(DYT3), and rapid-onset dystonia parkinsonism (DYT12). No positive linkage studies
have as yet been reported for autosomal recessive TD (DYT2) and in several other large
families with various types of dominantly inherited TD (DYT4). It may be anticipated
that the traditional clinical and etiological classifications of dystonia will increasingly
be replaced by a genetic one and that the identification of more dystonia genes may
lead to a better understanding of these largely nondegenerative disorders.
Keywords
Dystonia - genetics - review
