Evaluation of neurofibromatosis type 1 progression using a nationwide registry of patients who submitted claims for medical expense subsidies in Japan between 2008 and 2012.

The progression of neurological and bone manifestations was more prevalent in the 0-19 year age group compared to other age groups. The registry we used in the present study is useful for understanding the characteristics of patients with uncommon conditions, such as NF1. Our findings also highlight the feasibility of conducting quality research using registries of patients with rare diseases, such as NF1, that were not designed specifically for scientific research.