Variant allele frequency across all available specimens as detected with digital droplet PCR (Cases 1,2,3, and 5) or next-generation sequencing (Case 4). Data are presented mean +/− standard deviation. Case 1 (two separate surgeries): two specimens (1 and 2) were collected from a right frontal resection within the supplementary motor area, and 5 specimens (3, 4, 5, 6, and 7) were collected from the right frontal premotor region anterior to the precentral sulcus. Case 2: two specimens were collected from a parietal precuneate and posterior two thirds cingulate resection. Case 3: Two specimens were collected from a right posterior temporal-occipital resection. Case 4: A temporal lobe specimen was collected as part of a functional hemispherectomy. Case 5: A frontal lobe specimen was collected as part of a right frontal resection.