Nevertheless, NFNS may have different potential aetiologies and NFNS phenotype has been described also in patients with mutations in both the NF1 and PTPN11 genes [47] as well as in neurofibromatosis 1 (NF1) patients with Noonan-like features [48,49]. Here, PTPN11 is linked to neurofibromatosis-Noonan syndrome.