Fig. 4: Two-way hierarchical clustering heatmap of the top 30 serum metabolites and lipoproteins.

Top features ranked by t-test to retain the most contrasting patterns. Heatmap displays average features concentrations for each group (CTR, dn2PD, and advPD). The horizontal axis represents the groups, and the vertical axis represents 30 selected features concentrations in which features with similar trends cluster in rows. The magnitude of abundance change (“red” increased or “blue” decreased) is shown in accordance with the color scale on the right.