Drs. Lan Luo. Guangbin Xia, and S Subramony recently published “The Initial Clinical Presentation of Spinocerebellar Ataxias Type 1, 2, 3, and 6″, in Neurology April 5, 2016 vol. 86 no. 16 Supplement P6.393.
Objective: To characterize the initial clinical presentation of spinocerebellar ataxias (SCA) type 1, 2, 3, and 6.
Background: The SCAs are a group of genetically and clinically diverse neurodegenerative diseases and the understanding of initial clinical presentation of each SCA type will help pinpoint the clinical diagnosis.
Methods: The Clinical Research Consortium for Spinocerebellar Ataxias (CRC-SCA) enrolled 317 participants with SCA 1, 2, 3 and 6 from 12 medical centers in the United States. The initial presentation to ataxia specialist was recorded, including age of onset of any gait, speech, vision, and hand abnormalities. Since the majority of patients had gait abnormality as the first symptom, we divided SCA patients into two groups: gait onset group or non-gait onset group. We compared the number of pathological CAG repeats and the age of disease onset between the gait onset group and the non-gait onset group using t-test or the Wilcoxon Mann-Whitney test.
Results: The majority of SCA patients had gait problems initially and the percentage of these patients was similar across different types of SCAs (92.3[percnt] in SCA1, 87.0[percnt] in SCA2, 87.5[percnt] in SCA3, and 83.8[percnt] in SCA6, p= 0.59). The pathological CAG repeat expansions were similar between gait onset group and non-gait onset group in all four types of SCA patients. In addition, the disease onset for non-gait group in SCA2 patients was 9 years earlier than their counterpart (non-gait onset group 28.2 ± 14.8 years old vs. gait onset 37.2 ± 11.4 years old, p= 0.039). We did not observe any differences in disease onset between gait onset group and non-gait onset group in SCA1, 3, and 6.
Conclusions: Gait abnormality is the most common initial presentation of SCAs. Interestingly, SCA2 patients with non-gait onset tend to have a younger disease onset, which might represent a subtype of SCA2.