Birt–Hogg–Dubé Syndrome: A Mini Review of the Clinical Manifestations, Investigation, and Management

Birt-Hogg-Dubé (BHD) syndrome is a rare genetic disease, inherited in an autosomal dominant manner, that was first described in the mid-1970s and occurs due to pathogenic variants in the folliculin gene (<i>FLCN</i>) on chromosome 17p11.2. The syndrome has numerous clinical manifestations and primarily affects the lungs, kidneys, and skin. As far as the pulmonary features are concerned, more than 80% of patients appear to develop bilateral pulmonary cysts located in the lower lung zones, in the subpleural area, with cumulative risk of spontaneous pneumothorax depending on the number of cysts in the lungs. Another serious feature of the syndrome is the increased risk of renal cell carcinoma, which is often an incidental finding on screening or medical imaging. Cutaneous manifestations include benign fibrofolliculomas, trichodiscomas, and acrochordons (skin tags), which primarily affect the patients' emotional status as a result of their cosmetic defects. BHD syndrome is generally an underdiagnosed condition due to the great variability of its clinical picture, thus highlighting the importance of genetic testing for <i>FLCN</i> mutations in suspected cases. The application of ERN GENTURIS guidelines in clinical practice can facilitate early, accurate diagnosis of the disease and optimal personalized management of the patients.