Birt-Hogg-Dubé Syndrome: Clinicopathologic Findings and Genetic Alterations

The presence of BHD syndrome should be investigated in any patient with multiple bilateral kidney tumors, especially if the predominant histologic type is chromophobe renal cell carcinoma or the so-called hybrid oncocytic tumor. The genetic alteration for BHD syndrome has been mapped to chromosome 17p12q11, and the gene in this region has been cloned and believed to be responsible for the BHD syndrome. The function of the BHD product, called folliculin, is still unknown, although it is speculated to be a tumor suppressor gene. Numerous mutations have been described in the BHD gene. Studies are ongoing to determine the relationship between the BHD gene and development of sporadic renal cell carcinoma and other lesions.