FLCN and Birt-Hogg-Dube syndrome: Birt-Hogg-Dubé syndrome (BHD) is a genodermatosis characterised by benign skin lesions called fibrofolliculomas, lung cysts, pneumothorax and an increased risk for renal tumours.1–3 BHD is caused by mutations in the FLCN gene, of which the majority are truncating loss of function mutations.4 In the first report of BHD, two siblings with perifollicular fibromatosis were described.