FLCN and pneumothorax: Birt–Hogg–Dubé syndrome (BHDS, MIM #135150), caused by germline mutations of FLCN gene, is a rare autosomal dominant inherited disorder characterized by skin fibrofolliculomas, renal cancer, pulmonary cysts and spontaneous pneumothorax (Roth et al., 1993; Birt et al., 1977; Nickerson et al., 2002).