First, individuals with large (~1.4 Mb) genomic microdeletions, spanning the entire NF1 gene locus and neighboring genes, have more severe clinical phenotype, including increased number of neurofibromas, elevated risk for cardiac malfunction, skeletal anomalies, facial dysmorphism, malignant tumor development, and a higher prevalence of learning disabilities compared to patients with an intragenic NF1 mutation (Pasmant et al., 2010). This evidence concerns the gene NF1 and plexiform neurofibroma.