A novel FLCN gene mutation causing Birt-Hogg-Dubé syndrome in a Korean family.

Spontaneous pneumothorax is a common manifestation of Birt-Hogg-Dubé (BHD) syndrome, an inherited disorder caused by mutation of the folliculin (FLCN) gene. A 44-year-old female with a history of breast cancer was diagnosed with recurrent pneumothorax. Chest CT showed multiple cysts with left lung pneumothorax, and she received surgery for the diagnosis. Because the patient also had a family history of spontaneous pneumothorax, a FLCN genetic examination was conducted. A novel heterozygous, likely pathogenic variant (NM_144997.5:c.779+2T > C) was detected in the proband, her mother, and aunt. This is the first report of a new mutation of FLCN gene in a BHD syndrome patient.