NF1 and neurofibroma: More general observations have indicated a poorer cognitive prognosis and a higher risk of tumors, neurofibromas, and MPNSTs for the whole NF1 gene deletions [9,10,11]; other reports have hypothesized an association of splice-site mutations with an increased tendency to develop neoplasms [22], of truncating mutations with the presence of Lisch nodules and CALs [23,24] and of non-truncating mutations with pulmonary stenosis [25].