Sporadic hemangioblastomas demonstrate low somatic mutation rates, but have recurrent mutations in VHL . (a) Plot of the number of nonsynonymous mutations per megabase in hemangioblastomas in comparison to other primary tumors of the central nervous system, including medulloblastoma, craniopharyngioma, low grade glioma (LGG) and glioblastoma (GBM) . For comparison, the mutation rate of lung adenocarcinoma and melanoma are displayed . Each dot in this plot corresponds to a matched tumor-normal pair. The vertical position indicates the frequency of somatic mutations in that exome. The relative proportions of six different base-pair substitutions are indicated at the bottom. (b) Non-synonymous mutations in VHL observed in the discovery (triangle) and validation (circle) are illustrated. The average coverage depth of each exon for samples in the discovery cohort is indicated within parentheses.