Firstly, patients with large deletions of the NF1 gene region and flanking genes (NF1 microdeletions) tend to present a more severe phenotype in terms of cognitive impairment and/or learning disabilities, facial dysmorphisms and cardiovascular malformations, and are at increased risk of malignant peripheral nerve sheath tumours (MPNSTs) [53]. Here, NF1 is linked to Cognitive impairment.