In contrast, patients with large NF1 microdeletions, especially the type 1 deletion spanning 1.4 Mb and including genes like SUZ12 and RNF135, tend to experience more severe disease involving numerous tumors, cognitive impairment, overgrowth, cardiovascular anomalies, and a fourfold increased risk of MPNST [48,51]. Here, NF1 is linked to malignant peripheral nerve sheath tumor.