We applied this approach to RASopathies with the aim of finding molecular correlates of the mutational status in PBMCs, focusing on the two genes most frequently mutated in NS, PTPN11, and SOS1, and on SHOC2, which has been recently discovered to cause NS/LAH, a disorder with clinical overlap with the former [Cordeddu et al., 2009]. This evidence concerns the gene PTPN11 and Netherton syndrome.