FLCN and Birt-Hogg-Dubé syndrome: Of note, FLCN is mutated in Birt-Hogg-Dubé syndrome patients, where RagC/D activity and downstream regulation of TFEB/TFE3 seem to be particularly affected, highlighting FLCN-Rag-mTORC1-TFEB as an important signaling axis in human disease (Napolitano et al., 2020).