NF1 and neurofibromatosis type 1: The first suspicion of a causal link between these kinds of hereditary syndromes and defective RAS signaling arose when the loss of neurofibromin 1 (NF1), known to be a GAP for RAS GTPases [61] was found in association with the development of neurofibromatosis 1, one of the most common RASopathies.