FLCN and Birt-Hogg-Dubé syndrome: Birt-Hogg-Dubé syndrome (BHD, OMIM #315150) is an autosomal dominant condition caused by germline mutations in the FLCN gene encoding folliculin and is characterized by fibrofolliculomas, lung cysts, spontaneous pneumothorax and renal cell carcinoma (RCC) [1].