The ROC curve generated from the sPLS-DA model showed high discriminatory ability for stratifying HD mutation carriers from controls (Fig. 2F, AUC = 0.90, 95% CI: 0.79–1.00, P = 0.0006), similar to what was observed with PENK alone (Fig. 2A, AUC = 0.94). The gene discussed is PENK; the disease is Huntington disease.