NF1-associated astrocytomas usually sustain germline mutation of the NF1 gene located on chromosome 17q and somatic loss of the remaining NF1 allele, resulting in bi-allelic inactivation and loss-of-function to the NF1 gene (7, 8, 29, 30). The gene discussed is NF1; the disease is astrocytoma (excluding glioblastoma).