Profile of families with parkinsonism-predominant spinocerebellar ataxia type 2 (SCA2).
Spinocerebellar ataxia type 2 (SCA2) has been recognized recently as an uncommon cause of parkinsonism, an alternate presentation to the typical cerebellar disorder. This research review summarizes the existing literature on parkinsonism-predominant presentation SCA2 and presents new clinical cases of patients with this condition. Various phenotypes are noted in this subtype of SCA2, including parkinsonism indistinguishable from idiopathic Parkinson's disease (PD), parkinsonism plus ataxia, motor neuron disease, and postural tremor. In several kindreds with multiple affected family members, the SCA2 expansion segregated with disease; in addition, several single cases of parkinsonism with and without a family history are also described. The number of repeats in symptomatic patients ranged from 33 to 43. Interruption of the CAG repeat with CAA, CGG, or CCG was found in some individuals, possibly stabilizing the repeat structure and accounting for the relative stability of the repeat size across generations in some families; allele length is not necessarily indicative of trinucleotide repeat architecture. Positron emission tomography scanning in one family showed reduced fluorodopa uptake and normal to increased raclopride binding with a rostrocaudal gradient similar to that found in idiopathic PD. This review emphasizes the importance of testing for SCA2 in patients with parkinsonism and a family history of neurodegenerative disorders. Testing for SCA2 is also important in studies of inherited parkinsonism.
Furtado
Sarah
S
Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada. furtado@ucalgary.ca
Payami
Haydeh
H
Lockhart
Paul J
PJ
Hanson
Melissa
M
Nutt
John G
JG
Singleton
Andrew A
AA
Singleton
Amanda
A
Bower
Jamel
J
Utti
Ryan J
RJ
Bird
Thomas D
TD
de la Fuente-Fernandez
Raul
R
Tsuboi
Yoshio
Y
Klimek
Mary L
ML
Suchowersky
Oksana
O
Hardy
John
J
Calne
Donald B
DB
Wszolek
Zbigniew K
ZK
Farrer
Matthew
M
Gwinn-Hardy
Katrina
K
Stoessl
A Jon
AJ
D000978:Antiparkinson Agents / Q000627:therapeutic use; D001921:Brain / Q000098:blood supply / Q000378:metabolism / Q000473:pathology; D003342:Corpus Striatum / Q000098:blood supply / Q000378:metabolism; D050483:Dopamine Plasma Membrane Transport Proteins; D004421:Dystonia / Q000453:epidemiology; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use; D008279:Magnetic Resonance Imaging; D008562:Membrane Glycoproteins / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D020734:Parkinsonian Disorders / Q000188:drug therapy / Q000453:epidemiology / Q000235:genetics*; D011187:Posture; D020754:Spinocerebellar Ataxias / Q000188:drug therapy / Q000453:epidemiology / Q000235:genetics*; D014055:Tomography, Emission-Computed; D015899:Tomography, Emission-Computed, Single-Photon; D014202:Tremor / Q000188:drug therapy / Q000453:epidemiology
D000978:Antiparkinson Agents; D050483:Dopamine Plasma Membrane Transport Proteins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D007980:Levodopa