title: Early onset primary dystonia.
abstract: Dystonia is a syndrome characterized by sustained muscle contractions, frequently causing twisting and repetitive movements or abnormal postures. It is classified by age at onset, by distribution, and by aetiology. The aetiological classification distinguishes the following categories: primary, dystonia plus, secondary, heredo-degenerative and psychogenic dystonia. Primary dystonia is defined as clinical condition characterized by dystonia as the only neurological abnormality apart from tremor. Different genetic alterations and gene loci have been mapped in familial and sporadic patients. Early onset-primary dystonia (EO-PD) is the most severe form of primary dystonia, with clinical and genetic heterogeneity. It usually starts in one body part, subsequently spreads to involve other body regions with frequent generalization. DYT1 dystonia is transmitted as an autosomal dominant trait with reduced penetrance. The unique underlying mutation is a GAG deletion in the coding region of the TOR1A gene, located at chromosome 9q34. DYT16 dystonia is a novel recessive form of EO-PD, recently described in few patients, caused by mutations in the PRKRA gene located at chromosome 2q31. At least other two loci have been mapped, but there remains a large number of patients with EO-PD in whom no genetic alteration is discovered.
authors.affiliation: Department of Child Neurology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Via Celoria 11, 20133 Milano, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Zorzi
authors.forename: Federica
authors.initials: F
authors.lastname: Zibordi
authors.forename: Barbara
authors.initials: B
authors.lastname: Garavaglia
authors.forename: Nardo
authors.initials: N
authors.lastname: Nardocci
mesh_terms: D017668:Age of Onset; D002874:Chromosome Mapping; D002899:Chromosomes, Human, Pair 9; D020821:Dystonic Disorders / Q000145:classification / Q000235:genetics / Q000628:therapy; D020022:Genetic Predisposition to Disease; D006801:Humans; D018832:Molecular Chaperones / Q000235:genetics; D016601:RNA-Binding Proteins / Q000235:genetics; D017384:Sequence Deletion; D018911:Trinucleotide Repeats / Q000235:genetics
chemical_list: D018832:Molecular Chaperones; C104647:PRKRA protein, human; D016601:RNA-Binding Proteins; C108175:TOR1A protein, human