MAP2K2 and cardiofaciocutaneous syndrome: CFC is inherited in an autosomal-dominant manner and is caused by germline pathogenic variants in BRAF (75%), MAP2K1 (which encodes MEK1), MAP2K2 (which encodes MEK2) or, rarely, KRAS (Niihori et al., 2006; Rodriguez-Viciana et al., 2006).