The RAS-MEK-ERK pathway represents a chain of protein signalling pathway that responds to a mitogen binding to a cell surface receptor. The RAS-MEK-ERK pathway represents a chain of protein signalling pathway that responds to a mitogen binding to a cell surface receptor. This chain of protein communications occurs through sequential protein phosphorylation and ends up by affecting the nuclear DNA transcription leading to different cellular changes. Abnormalities of certain factors along the pathway can lead to cardiocutaneous syndromes. Tara Bardawil et al. Open Heart 2016;3:e000442 ©2016 by British Cardiovascular Society