Introduction Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder occuring in 1 out of 3500 living newborns. The disease is caused by heterozygous mutations of the NF1 gene, located on chromosome 17q11.2. The NF1 gene encodes the tumor suppressor neurofibromin, a negative regulator of the RAS/MAPK pathway. In approximately 95% of patients, the heterozygous mutation is intragenic. The remaining 5% of patients are carrier of a microdeletion, mostly the type 1 deletion, in which apart from the NF1 gene, 14 additional protein coding genes are located.