FLCN and Birt-Hogg-Dubé syndrome: Birt-Hogg-Dubé syndrome (BHD) is an autosomal dominant disease caused by mutations of germline folliculin (FCLN) mapped in the chromosome 17p11.2 region, and it commonly accompanies renal tumors; skin conditions such as fibrofolliculomas, trichodiscoma, and acrochordon; multiple pulmonary cysts; and spontaneous pneumothorax [1-3].