NPHS1 and neurofibromatosis type 1: A population-based study conducted in Wales demonstrated that over 99% of adults with NF1 had cNF lesions and that the number of lesions increased with age.7 A subsequent cross-sectional study of 728 pediatric and adult patients with NF1 also showed that the number of cNF lesions increased with age (figure 1).8 In addition to age, hormones and pregnancy have been hypothesized to influence the development of cNF.9