Comprehensive Molecular Genetic Diagnostics of Birt-Hogg-Dube Syndrome in a Russian Patient with Renal Cancer and Lung Cysts: A Case Report

We report a case of Birt-Hogg-Dube syndrome (BHDS), a rare hereditary syndrome, the main visible sign of which is the development of multiple skin fibrofolliculomas. In our case, there was a manifestation of BHDS consisting in the absence of fibrofolliculomas and presence of other characteristic features of this syndrome: lung cysts and renal cancer. The 26-year-old woman was admitted to a clinic for diagnosis and treatment of a neoplasm of the left kidney and had a history of renal cell cancer (RCC) of the right kidney and spontaneous pneumothorax. Multiple tumors of the left kidney and lung cysts were observed upon clinical and laboratory testing. Tumors of the left kidney were resected and diagnosed by a pathologist as chromophobe RCC. Sequencing of FLCN exons 4–14 from blood DNA revealed the heterozygous germline nonsense mutation c.1429C>T (p.R477*), confirming the diagnosis of BHDS. Several somatic variants were detected by tumor DNA sequencing using the Comprehensive Cancer Panel and Ion S5 platform. Medical-genetic counseling was conducted, and follow-up management was outlined. To our knowledge, this case report is the first comprehensive clinical and genetic examination of a patient with BHDS in Russia. The p.R477* mutation has been described by other authors in patients with fibrofolliculomas and lung cysts, but not in those with RCC, while RCC was the first manifestation of BHDS in our case. The case report may help geneticists, oncologists, and other specialists to better understand the clinical and genetic heterogeneity of BHDS in various populations