DYT6 in Brazil: Genetic Assessment and Clinical Characteristics of Patients.
BACKGROUND
Several genes associated with dystonia have been identified. A mutation in one of these, THAP1 (DYT6), is linked to isolated dystonia. The aim of this study was to assess the prevalence of THAP1 gene mutations and the clinical characteristics of patients with these mutations in a clinical population in Brazil.


METHODS
Seventy-four patients presenting with dystonia involving the cervical muscles and without mutations in the TOR1A (DYT1) gene or any other movement disorders were recruited at a movement disorders clinic between June 2008 and June 2009. All the patients underwent clinical examination and were screened for mutations of the THAP1 gene.


RESULTS
Three patients had the novel p.Gln97Ter THAP1 nonsense mutation in heterozygosis. One of them had no family history of dystonia. Symptoms in this patient first appeared in his right arm, and the condition progressed to the generalized form. The other two patients belonged to the same family (cousins). Symptoms in the first patient started in her right arm at the age of 18 years and the condition progressed to the segmental form. The second patient, who carried the p.Arg169Gln missense mutation, developed dystonia in her left arm at the age of 6 years. The condition progressed to generalized dystonia.


CONCLUSIONS
We conclude that THAP1 mutations are also a cause, albeit uncommon, of segmental and generalized dystonia in the Brazilian population.
Movement Disorders Unit, Neurology Service, Hospital de Clínicas, Federal University of Paraná, Curitiba, Brazil ; Neurology Service, Medicine Department, Hospital Universitário, State University of Ponta Grossa, Ponta Grossa, Brazil.
Carlos Henrique F
CH
Camargo
Movement Disorders Unit, Neurology Service, Hospital das Clínicas, Belo Horizonte, Brazil.
Sarah Teixeira
ST
Camargos
Genetika Laboratory and Catholic University of Paraná, Curitiba, Brazil.
Salmo
S
Raskin
Movement Disorders Unit, Neurology Service, Hospital das Clínicas, Belo Horizonte, Brazil.
Francisco Eduardo C
FE
Cardoso
Movement Disorders Unit, Neurology Service, Hospital de Clínicas, Federal University of Paraná, Curitiba, Brazil.
Hélio Afonso G
HA
Teive
DYT1; DYT6; Dystonia; cervical dystonia; movement disorders