 Recruitment will be focused on identifying individuals with a range of severity of the primary sub-phenotype, spinal neurofibroma burden. We will primarily recruit post-pubertal individuals who meet the 1988 NIH criteria for neurofibromatosis type 1 NIH Consensus Development Conference 1988. We will exclude those with recognized segmental or mosaic NF1. The rate of cutaneous neurofibroma growth and number is known to vary widely; these tumors typically appear in adolescence. For this reason we will ascertain patients after puberty. We expect most individuals to be 18 years or older, but will also accept post-pubertal pediatric patients and use a hand film to demonstrate bone age. Parents whether affected or not are critical when using family-based tests of association like the TDT and tests of linkage and will also be recruited. 