Subsequently, mutations in KRAS [56, 57], SOS1 [58, 59], RAF1 [60, 61], NRAS [62], HRAS [63], BRAF [56, 64], SHOC2 [65], MAP2K1 (MEK1) and MAP2K2 (MEK2) [64], CBL [66] and NF1 [67] have been associated with RASopathies in which CHD are observed (Table 1). Here, MAP2K1 is linked to RASopathy.