Mutations in the FLCN gene, which provide instructions for making the protein folliculin, are present in the brain, heart, placenta, testis, skin, lungs, and kidneys, and may be important for foreign particle endocytosis, which can result in a variety of benign tumors.20 It appears that these patients most commonly see a dermatologist for recurrent skin lesions on the face and neck, usually around the age of 20 to 30. The gene discussed is FLCN; the disease is benign neoplasm.