Salivary gland tumors that developed in BHD patients exhibited an upregulated mTOR-S6R pathway as well as increased GPNMB expression, which are characteristics of FLCN-deficient cells.
These findings suggest that the decreased FLCN expression itself without producing mutated folliculin proteins can be at risk for developing clinical manifestations of BHDS: fibrofolliculomas, lung cysts, and tumorigenesis in the kidneys.
Birt-Hogg-Dubé (BHD) syndrome is associated with the development of hereditary renal cell carcinoma (RCC) and is caused by a germline mutation in the folliculin gene.
The literature has reported cases diagnosed with familial PSP, who have no manifestations of Birt-Hogg-Dubé (BHD) syndrome but mutations in different exons of the Folliculin (FLCN) gene.
The Birt-Hogg-Dubé (BHD) syndrome related protein FLCN has recently been implicated in the vesicular trafficking processes by interacting with several Rab family GTPases.
Birt-Hogg-Dubé syndrome (BHD, also referred to as Hornstein-Knickenberg syndrome) is an autosomal dominant tumor syndrome caused by mutations in the FLCN gene located on chromosome 17.
The diagnosis of BHDS was established by folliculin (FLCN) genetic testing, and the results were compared to the histopathological findings of FFs or trichodiscomas (TDs).
Ongoing research efforts are focused on clarifying the primary FLCN-associated pathway(s) that drives the development of fibrofolliculomas, lung cysts and kidney tumors in BHD patients carrying germline FLCN mutations.
Mutations in the FLCN gene are the cause of Birt-Hogg-Dubé syndrome, a rare tumor syndrome which is characterized by the combination of renal cell carcinoma, pneumothorax and skin tumors.
The Birt-Hogg-Dubé (BHD) syndrome is a very rare autosomal dominant form of genodermatosis caused by germline mutations in the folliculin (FLCN) gene, which is mapped to the p11.2 region in chromosome 17.