FLCN and pneumothorax: Birt–Hogg–Dubé syndrome (BHDS) (MIM 135150) is an autosomal dominantly inherited genodermatosis that predisposes to the development of cutaneous hamartomas (fibrofolliculomas), kidney neoplasms, lung cysts and spontaneous pneumothorax.1, 2 We mapped the BHD locus to the short arm of chromosome 17(17p11.2).3 Subsequently, we found that germline mutations in BHD (GenBank accession number AF517523) (also known as FLCN), were associated with the susceptibility for BHDS.4BHD is composed of 14 exons.