Neurofibromatosis Type 1 (NF1) is characterised by loss of the NF1 gene that encodes neurofibromin [27], [70], [71] and persons affected are predisposed to develop benign peripheral nerve sheath tumours (or neurofibromas), myeloid leukemia, hyperpigmentation of the skin and learning disabilities [72]–[74]; moreover, persons with a loss of heterozygosity of NF1 alleles develop malignant peripheral nerve sheath tumours [75]. This evidence concerns the gene NF1 and plexiform neurofibroma.