Impaired body movement representation in DYT1 mutation carriers.
OBJECTIVE
The only known genetic cause of early-onset primary torsion dystonia is the GAG deletion in the DYT1 gene. Due to the reduced penetrance, many mutation carriers remain clinically asymptomatic, despite the presence of subclinical abnormalities, mainly in the motor control circuitry. Our aim was to investigate whether the DYT1 mutation impairs the inner simulation of movements, a fundamental function for motor planning and execution, which relies upon cortical and subcortical systems, dysfunctional in dystonia.


METHODS
DYT1 manifesting patients, DYT1 non-manifesting carriers and control subjects were asked to fixate body (hand, foot, face) or non-body (car) stimuli on a computer screen. Stimuli were presented at different degrees of orientations and subjects had to mentally rotate them, in order to give a laterality judgement. Reaction times and accuracy were collected.


RESULTS
DYT1 carriers, manifesting and non-manifesting dystonic symptoms, were slower in mentally rotating body parts (but not cars) than control subjects.


CONCLUSIONS
The DYT1 gene mutation is associated with a slowness in mental simulation of movements, independently from the presence of motor symptoms.


CONCLUSIONS
These findings suggest that the cognitive representation of body movements may be altered subclinically in dystonia, thus contributing to the endophenotypic trait of disease.
Fiorio
M
M
Department of Neurological and Vision Sciences, Section of Rehabilitative Neurology, University of Verona, Via Casorati 43, 37131 Verona, Italy. Electronic address: mirta.fiorio@univr.it.
Gambarin
M
M
Department of Neurological and Vision Sciences, Section of Rehabilitative Neurology, University of Verona, Via Casorati 43, 37131 Verona, Italy.
Defazio
G
G
Institute of Neurology, University of Bari, Italy.
Valente
E M
EM
IRCCS CSS, Mendel Institute, Rome, Italy; Operative Unit of Pediatric Genetics and Immunology, Department of Medical and Surgical Pediatric Sciences, University of Messina, Italy.
Stanzani
C
C
Department of Neurological and Vision Sciences, Section of Rehabilitative Neurology, University of Verona, Via Casorati 43, 37131 Verona, Italy.
Moretto
G
G
Neurology Unit, Borgo Trento Hospital, Verona, Italy.
Loi
M
M
Neuropsychiatry Department, G. Brotzu Hospital, Cagliari, Italy.
Soliveri
P
P
National Neurology Institute, "C. Besta", Milan, Italy.
Nardocci
N
N
National Neurology Institute, "C. Besta", Milan, Italy.
Albanese
A
A
National Neurology Institute, "C. Besta", Milan, Italy.
Fiaschi
A
A
Department of Neurological and Vision Sciences, Section of Rehabilitative Neurology, University of Verona, Via Casorati 43, 37131 Verona, Italy.
Tinazzi
M
M
Department of Neurological and Vision Sciences, Section of Rehabilitative Neurology, University of Verona, Via Casorati 43, 37131 Verona, Italy; Neurology Unit, Borgo Trento Hospital, Verona, Italy.
D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D002648:Child; D004252:DNA Mutational Analysis; D004421:Dystonia / Q000235:genetics* / Q000503:physiopathology*; D005260:Female; D007839:Functional Laterality / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D018832:Molecular Chaperones / Q000235:genetics*; D009068:Movement / Q000502:physiology*; D009154:Mutation / Q000235:genetics*; D009949:Orientation / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods; D011187:Posture; D011597:Psychomotor Performance; D011930:Reaction Time / Q000235:genetics; D018911:Trinucleotide Repeats / Q000235:genetics*
D018832:Molecular Chaperones; C108175:TOR1A protein, human