SOS1 and RASopathy: Of note, the signatures obtained separately for the PTPN11, SOS1, and SHOC2 mutations were found to discriminate more efficiently the individual mutation groups from controls, compared to the signature characterizing the entire “RASopathy” cohort of PBMCs with mutated PTPN11, SOS1, and SHOC2 alleles, indicating occurrence of significant heterogeneity among subgroups.