MAP2K1 and cardiofaciocutaneous syndrome: The mutation genes involved in CFC syndrome are BRAF (7q34) in up to 75% of the cases, MAP2K1 (15q22.1-q22.33) and MAP2K2 (19p13.3), both around 25% of the cases, and KRAS (12p12.1) present in less than 2% of the cases.