NF1 and central nervous system cancer: Consistent with an autosomal dominant tumor predisposition syndrome, these gliomas arising in the setting of NF1 developed in patients with a heterozygous germline mutation or deletion involving one of two NF1 alleles (apart from patients #2 and #19), with tumors that developed following somatic inactivation of the remaining wildtype allele through either loss of heterozygosity (LOH) or a second tumor-acquired mutation.