Birt-Hogg-Dubé syndrome, a genodermatosis that increases risk for renal carcinoma

Over the past decade cancer-causing genes have been identified for the most common histologic types of renal cancer, specifically clear cell, papillary type 1 and papillary type 2. Genes predisposing to the more rare chromophobe renal carcinoma and renal oncocytoma were unknown until the recent discovery of a novel gene, BHD, on chromosome 17p that was found to be mutated in the germline of affected family members with the Birt-Hogg-Dubé (BHD) syndrome. These patients develop the hallmark BHD skin lesions (fibrofolliculomas), lung cysts and spontaneous pneumothorax. Importantly, BHD patients have an increased risk for developing a variety of renal neoplasia, most commonly chromophobe and oncocytic hybrid tumors. This review will describe the phenotypic manifestations of BHD including the histologic features of BHD-associated renal tumors, the identification of this novel renal cancer-predisposing gene, the BHD mutation spectrum found in BHD patients, and will discuss the potential role of BHD as a tumor suppressor gene.