Individuals affected with Neurofibromatosis type 2 (NF2) typically develop multiple brain and spine tumours, and often lose hearing in young adulthood. The disease course can vary amongst patients and their severity is linked to genetic variations. The NF2 genetic severity score presented here, groups patients using genetic test results. The score separated patients according to 10 different outcomes, including age at diagnosis and number of interventions. This score will allow genetic information to be routinely incorporated in studies delineating the natural history of NF2, and in future studies assessing NF2 treatment response. (By Dorothy Halliday, http://jmg.bmj.com/content/early/2017/08/28/jmedgenet-2017-104519 )