Birt-Hogg-Dubé Syndrome

A 35-year-old man presents with multiple skin-colored dome-shaped papules on his face and neck that have been slowly enlarging over the past 5 years. He also reports a recent episode of spontaneous pneumothorax. Genetic testing reveals a pathogenic mutation in the FLCN gene located at the locus marked **B** in the diagram. Which of the following best describes the molecular consequence of this mutation in Birt-Hogg-Dubé syndrome?

A 38-year-old man presents to the pulmonology clinic with a history of recurrent bilateral pneumothorax over the past 2 years. On examination, he has multiple dome-shaped, skin-colored papules (1–5 mm) on his face and neck, and HRCT chest shows multiple basilar, lentiform-shaped pulmonary cysts. Genetic testing confirms loss-of-function mutations in the FLCN gene on the inheritance pattern marked **B** in the diagram. Which of the following best describes the inheritance pattern and molecular basis of this condition?