Neurofibromatosis type 1 (NF1) is a genetic condition that can cause a wide range of medical issues, with symptoms varying greatly between individuals. In this study, we analyzed over 100 patients with specific NF1 gene mutations and found that some of these variants are consistently associated with milder or more severe forms of the disease. Notably, we identified a new group of variants linked to an absence of tumors. These findings enhance our understanding of NF1 and may help doctors better predict patient outcomes and personalize care based on genetic information. (By Professor Eric Pasmant, https://jmg.bmj.com/content/early/2025/08/04/jmg-2025-110783 )