Background: Familial spontaneous pneumothorax is one of the characteristics of Birt-Hogg-Dube syndrome (BHDS), which is an autosomal dominant disease caused by the mutation of folliculin (FLCN). Aim: To investigate the mutation of FLCN gene in a familial spontaneous pneumothorax. Design: Prospective case study. Methods: Clinical and genetic data of a Chinese family with four patients who presented spontaneous pneumothorax in the absence of skin lesions or renal tumors were collected. CT scan of patient's lung was applied for observation of pneumothorax. DNA sequencing of the coding exons (4-14 exons) of FLCN was performed for all 11 members of the family and 100 unrelated healthy controls. Results: CT scan of patient's lung showed spontaneous pneumothorax. A mutation (c. 510C > G) that leads to a premature stop codon (p. Y170X) was found in the proband using DNA sequencing of coding exons (4-14 exons) of FLCN. This mutation was also observed in the other affected members of the family. Conclusions: A nonsense mutation of FLCN was found in a spontaneous pneumothorax family. Our results expand the mutational spectrum of FLCN in patients with BHDS.