NF1 and plexiform neurofibroma: 2000). Many features of NF1 increase in frequency with age: nearly all by the age of 12 years and all by 20 years. In fact, the majority of these patients not fulfilling the NIH criteria display CALs and minor features (Table S1). Adults that did not fulfill NIH criteria showed neurofibromas, CALs or both, but fell below the threshold for NIH diagnosis (Table S1). 11% of these adults (6 on 56/159) were oligosymptomatic cases with NF1 mutations (Table 1).