The plausibility of a role for this transcription factor in ADPKD is supported by the renal cystic phenotypes observed in transgenic mice that overexpress TFEB (6) and in patients with Birt-Hogg-Dubé (BHD) syndrome [for a review, see Daccord et al. (7)], which arises due to mutations in the folliculin (FLCN) gene, is associated with Tfeb pathway activation, and is recapitulated in both Flcn knockout (KO) (8, 9) and double genetic KO of its interacting proteins, folliculin-interacting proteins 1 and 2 (Fnip1 and Fnip2, respectively) (10), in animal models. The gene discussed is FNIP1; the disease is autosomal dominant polycystic kidney disease.