Fig. 7: Investigation of clinical and biological parameters discriminant of PD endophenotypes.

a Dot plots of clinical variables with the highest between-cluster discriminative capacity: GI survey ‘daily frequency of defecation’ [0 to 3, indicating less-than-once to 3 times per day], Bristol Stool Scale, GSRS ‘increased flatus’, self-reported presence of constipation yes[1]/no[0], GSRS scale total score. Medians for each cluster are indicated by black dots. b Heatmap of normalised immune variables used in clustering analysis, with rows labelled with PD participant identifier code and colour-coded according to cluster identity (nPD cluster blue, n = 14; cPD cluster pink, n = 14). Immune metrics columns are coloured according to immune cell type and ordered by hierarchical clustering. Heatmap colouring reflects relative upregulation (red + 3 SD) or downregulation (blue -3 SD) of immune metrics among PD participants. c−f Boxplots showing between-cluster differences in: (c) TNFα + CD4 T cell frequency, (d) faecal formate concentration, (e) faecal propionate concentration, and (f) plasma creatine concentration. Statistical comparisons of clinical variables were performed using Fisher’s exact test (binary response) or Wilcoxon rank-sum test (ordinal scale response). Between-cluster comparisons of biological parameters were performed by t-test or Wilcoxon rank-sum test according to variable distribution. *p < 0.05 was considered statistically significant.