Clinical relevance of FLCN mutations in Asian patients with Birt-Hogg-Dubé syndrome

<bold>Introduction:</bold> Birt-Hogg-Dubé syndrome (BHDS) is a rare, autosomal dominant genetic disorder featured by the development of fibrofolliculoma, renal cell carcinoma and lung cysts. Methods：From 2019 to 2024,52 patients with BHDS have been diagnosed in our department. The diagnosis of 47 patients were confirmed via direct FLCN sequencing, and three according to their characteristic clinical and radiological presentations. Result：There were 52 (45 Females, 7Males) patients diagnosed with BHD in our group, the average age was 48.41 years (range: 19-75 y). All patients are Asian, Three patients were ex-smokers, 34.62%(18/52) patients had a family history of pulmonary bulla or pneumothorax. 63.46%(33/52) patients have experienced less of breath, and 53.85% (28/52)patients has a cough experience.only four patients had skin lesions at the time of diagnosis ,and only three paient had renal hamartoa occurred. CT scans were available for 52 patients,65.38%(34/52) Patients had a history of recurrent symptomatic pneumothorax. 29 out of 52 patients had pulmonary function tests, Other patients did not have lung function done because they had a recurrent pneumothorax within six months or for other reasons. Among 52 patients, with 5 case unknow, 60.71% (17/28) patients were found to have alveoli in pathological diagnosis. In 43 out of the 52 patients ,FLCN mutations were identifird as likely or confirmed pathogenicity. <bold>Conclusions:</bold> The proportion of Asian patients with skin symptoms and renal symptoms is low, and further diagnosis and treatment should be combined with family history, FLCN mutation test and clinical characteristics.