Fig. 2

K-means cluster analysis with the hierarchical clustering of the fold change values (case versus control). Included are the metabolic features having p value <0.05 and fold change value ≥±1.2. The clusters are numbered one–four as depicted in the figure. The values for peak areas were row-wise normalized, and the colour scale indicates high (red) or (low) metabolite level. Grey colour in the heat map indicates not detected value