Our data provide strong support to the hypothesis that the S230W variant of <i>YWHAZ</i> is a gain-of-function mutation in the RAS-ERK pathway and may underlie a CFC phenotype.
However, despite reduced levels of MEK1 protein and the lower abundance of MEK1 Y130C protein than wild type, <i>Mek1</i><sup>Y130C</sup> mutants showed increased ERK (MAPK) protein activation in response to growth factors, supporting a role for MEK1 Y130C in hyperactivation of the RAS/MAPK pathway, leading to CFC.
These results suggest that our new Braf knockin mice recapitulate major features of RASopathies and that epigenetic modulation as well as the inhibition of the ERK pathway will be a potential therapeutic strategy for the treatment of CFC syndrome.
Recently, we identified mutations in KRAS and BRAF in 19 of 43 individuals with CFC syndrome, suggesting that dysregulation of the RAS/RAF/MEK/ERK pathway is a molecular basis for CFC syndrome.