Normal tissues from adults with neurofibromatosis type 1 are grouped by tissue type and evaluated for an excess of nonsynonymous variants in NF1 and compared with the index children. Top, d N /d S ratios for truncating mutations (the dot represents the maximum likelihood estimate, and the lines represent the 95% credible interval); middle, counts of variants in NF1 ; bottom, total duplex coverage ( Methods ; Supplementary Note ) over NF1 in each group. R, right; L, left; MES, mesoderm; WT, wild type.