Table 1. Demographic features of patients with SCA.

	SCA 1 (n = 52); P	SCA 2 (n = 64); P	SCA 3 (n = 117); P	SCA 6 (n = 68); P	P
Gender (male), n (%)	22 (42%); 0.47	29 (45%); 0.78	58 (50%); 0.45	32 (47%); 0.97	0.84
Race (white), n (%)	49 (94%); <0.001	50 (78%); 0.41	62 (53%); <0.001	62 (91%); <0.001	<0.001
Age, yr	49.6 (12.5); 0.022	49.3 (13.0); 0.004	51.0 (11.5); 0.011	64.5 (10.8); <0.001	<0.001
Age of onset, yr	40.5 (11.3); 0.31	35.4 (11.4); <0.001	40.3 (11.4); 0.053	52.6 (9.9); <0.001	<0.001
Disease duration, yr	9.2 (7.1); 0.041	13.7 (8.5); 0.003	10.5 (7.2); 0.16	12.1 (9.9); 0.38	0.013
SARA score	14.0 (8.6); 0.16	17.7 (7.2); 0.004	15.1 (8.9); 0.39	14.8 (7.4); 0.59	0.033
UHDRS	17.8 (6.2); 0.28	17.1 (6.3); 0.77	16.4 (6.5); 0.23	17.2 (5.7); 0.90	0.60
Functional stage	2.8 (1.3); 0.11	3.0 (1.2); 0.96	3.1 (1.3); 0.61	3.1 (1.3); 0.37	0.44

Values are reported as mean (SD); P value, unless otherwise noted. The P-value under each data point represents a comparison of that particular SCA against all other SCAs. These P-values were calculated with χ² tests for categorical variables, t test for continuous variables, and Wilcoxon–Mann–Whitney test for nonparametric variables. The P-value in the final column represents the comparison of each individual SCA (4-group comparison). The final column P-value was calculated with χ² tests for categorical variables, analysis of variance for continuous variables, and Kruskal–Wallis for nonparametric variables.

SARA, Scale for Assessment and Rating of Ataxia; SCA, spinocerebellar ataxia; UHDRS, Unified Huntington Disease Rating Scale.