Table 3.

Multiple linear models testing the association between the HD phenotype and various explanatory variables

Model		r2	p value for model	Parameter values
				Sample size	Explanatory variable	Effect in years	p value for explanatory variable
1	Ln (AoD)∼ CAG + allele structures + expansion score	0.625	1.296 × 10−9	60	CAG	−3.504	1.56 × 10−11
				2	Q1-0-0-9-2	−11.491	0.034
				30	Q1-2-0-9-2	−10.180	4.20 × 10−5
				4	Q1-2-2-6-3	−0.840	0.846
				1	Q1-4-2-4-3	−5.903	0.411
					Expansion score	−10.600	0.012
2	Ln (AoD)∼ CAG + haplotypes + expansion score	0.664	2.989 × 10−8	60	CAG	−3.665	8.93 × 10−11
				1	A2a	2.050	0.784
				1	A2b	11.664	0.163
				1	A4a	12.985	0.137
				4	A4b	15.765	3.28 × 10−3
				1	B1	29.224	3.37 × 10−3
				1	C4	2.773	0.719
				16	C5	14.250	1.41 × 10−4
				4	C9	11.517	9.37 × 10−3
					Expansion score	−12.090	7.81 × 10−3

The statistically significant explanatory variables are indicated in italics. Model 1. Linear model testing the association of the CAG repeat length, allele structure and expansion score on the AoD, relative to the grouped typical allele structure Q¹-2-2-P²-2. The R-square and p values of the overall model show a significant association (r² = 0.63, p = 1 × 10⁻⁹), the CAG repeat length, allele structures Q¹-0-0-9-2 and Q¹-2-0-9-2, and expansion score had a significant association. Model 2. Linear model testing the association of the CAG repeat length, background haplotype, and expansion score on the AoD, relative to the most common haplotype B2. The R-square and p values of the overall model show a significant association (r² = 0.66, p = 3 × 10⁻⁸), and the CAG repeat length; haplotypes A4b, B1, C5, and C9; and expansion score had a significant association.