Although available information supports the view that SOS1 is not mutated in cardiofaciocutaneous syndrome (CFCS; MIM♯ 115150) [Zenker et al., 2007a], a condition clinically related to NS, a few individuals with ectodermal manifestations and distinctive facial dysmorphism that might be suggestive of CFCS have recently been reported has having SOS1 mutations [Narumi et al., 2008; Nystrom et al., 2008]. Here, SOS1 is linked to cardiofaciocutaneous syndrome 1.