Figure 1

Inverse correlation of age at neurologic onset and HD CAG repeat length. The plot shows data points from 1,200 HD subjects of known age at neurologic onset. For each individual, the measured CAG repeat length in blood DNA (x-axis) is plotted against age at neurologic onset (y-axis). The line represents the best-fit simple logarithmic regression to the data. The CAG repeat length accounts for approximately 67% of the overall variation in age at neurologic onset, and the remaining variation shows a heritability of approximately 0.56.