Supplementary Figure 10: Building a l λ CAG/age lookup table.

The figure outlines the procedure for building a reverse map connecting the 1-dimensional values of the dependent variable (λ) back to the corresponding values of (normalized) CAG length and Age, which is achieved by constructing a lookup table. Each pixel (R/G/B=0 pair) is enumerated, i.e. assigned a value from 1 to N in a continuous manner as shown in the figure. The normalized [CAG,Age] (i.e. [R,G]) matrix is traversed from the lower left to the upper right corner along each subsequent diagonal enumerating (assigning next available integer value) every coordinate pair. At the end, the resulting 1D array is also normalized to the [0..1] range. Note that small λ (around 0) in this enumeration scheme correspond to the low CAG and low Age values, whereas high λ (around 1) correspond to high CAG and high Age.