Saccade velocity is reduced in presymptomatic spinocerebellar ataxia type 2.
OBJECTIVE
A characteristic feature of spinocerebellar ataxia type 2 (SCA2) is saccadic slowing at early disease stages. We sought to determine whether this sign is detectable before clinical manifestation and quantifies the disease progression throughout life in linear fashion.


METHODS
In a specialized ataxia clinic, 54 presymptomatic carriers of SCA2 polyglutamine expansions and 56 relatives without mutation were documented with regard to their maximal saccade velocity (MSV).


RESULTS
Among the control individuals, a significant effect of aging on MSV was observed. After elimination of this age influence through a matched-pair approach, a presymptomatic decrease of MSV could be shown. The MSV reduction was stronger in carriers of large expansions. In the years before calculated disease manifestation, the MSV impairment advanced insidiously.


CONCLUSIONS
Saccade velocity is a sensitive SCA2 endophenotype that reflects early pontine degeneration and may be a useful diagnostic parameter before the onset of ataxia.


CONCLUSIONS
Future neuroprotective therapies of polyglutamine neurodegeneration may be assessed by MSV from earliest to prefinal disease stages.
Velázquez-Pérez
L
L
Centro para la Investigación y Rehabilitación de las Ataxias Hereditarias (CIRAH), Holguín, Cuba.
Seifried
C
C
Abele
M
M
Wirjatijasa
F
F
Rodríguez-Labrada
R
R
Santos-Falcón
N
N
Sánchez-Cruz
G
G
Almaguer-Mederos
L
L
Tejeda
R
R
Canales-Ochoa
N
N
Fetter
M
M
Ziemann
U
U
Klockgether
T
T
Medrano-Montero
J
J
Rodríguez-Díaz
J
J
Laffita-Mesa
J M
JM
Auburger
G
G
D000293:Adolescent; D000328:Adult; D000368:Aged; D000067528:Ataxins; D002531:Cerebellum / Q000503:physiopathology; D018450:Disease Progression; D042241:Early Diagnosis; D005260:Female; D006579:Heterozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000235:genetics; D009434:Neural Pathways / Q000503:physiopathology; D015835:Ocular Motility Disorders / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology*; D009801:Oculomotor Muscles / Q000294:innervation / Q000503:physiopathology*; D011237:Predictive Value of Tests; D011379:Prognosis; D012438:Saccades / Q000502:physiology*; D020754:Spinocerebellar Ataxias / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology*; D055815:Young Adult
D000067528:Ataxins; D009419:Nerve Tissue Proteins