Tfe3-gene fusions can be causal for renal cell carcinomas, which also occur in tuberosclerosis due to mutations in Tsc1 or Tsc2 and in Bird-Hogg-Dubé (BHD) syndrome due to Flcn mutations (Armah and Parwani, 2010; Linehan et al., 2010). The gene discussed is TSC1; the disease is hereditary clear cell renal cell carcinoma.