NF1 and plexiform neurofibroma: (2012) showed that an extremelyhigh burden of internal neurofibromas, characterised by >3000 ml tumour volumeas determined by whole-body MRI, was significantly more frequent in non-mosaictype-1 and type-2 NF1 microdeletion patientsthan in NF1 patients with intragenic lesions (13 vs. 1%).