**3. Results**

The participants from the Kids-JOHD study had a significant nonlinear relationship between AMO and CAG repeat length (*R<sup>2</sup>* = 0.84, *p* = 2.63 × <sup>10</sup>−10) (Figure 2A). As has been reported previously, we also observed significant nonlinear relationships between AMO and CAG repeat length using data from participants with AOHD from the Predict-HD and Enroll-HD studies. From Predict-HD, the *R<sup>2</sup>* value was 0.59 (*p* = 2.2 × <sup>10</sup>−16) (Figure 2B). The results from participants from Enroll-HD closely matched those observed in Predict-HD. Specifically, the R<sup>2</sup> value was 0.57 (*p* = 2.2 × <sup>10</sup>−16) (Figure 2C).

**Figure 2.** Cytosine–adenine–guanine (CAG) repeat length significantly predicts the age of motor onset in (**A**) patients with juvenile-onset Huntington's disease (JOHD) from the Kids-JOHD study, (**B**) patients with adult-onset Huntington's Disease (AOHD) from the Predict-HD study, and (**C**) patients with AOHD from the Enroll-HD study. Black lines show the predicted regression lines, and the gray ribbons display the 95% confidence intervals.
