Fig. 5

A Serotonin levels (ng/ml) measured in platelet-rich plasma of 21 intrafamilial PMS affected-unaffected sibling pairs; B Mean (± SD) serotonin levels measured in 53 PMS patients, 20 PMS unaffected siblings, 432 iASD patients, and 115 unaffected siblings of individuals with iASD. **p < 0.01, ***p < 0.001 after Bonferroni correction