AB111. Features of Birt-Hogg-Dubé syndrome patients in East Asian countries

OBJECTIVE: Birt-Hogg-Dubé (BHD) syndrome is an inherited renal cancer syndrome caused by mutations in FLCN gene and characterized by the presence of fibrofolliculomas, pulmonary cysts, spontaneous pneumothoraces and renal cell carcinomas. Only a few BHD syndrome cases were reported from Asian countries, more cases are needed to analysis the genotype-phenotype of this disease. METHODS: Two Chinese patients with renal cell carcinomas and spontaneous pneumothoraces but no fibrofolliculomas were suspected of having BHD syndrome. Genomic DNA was extracted from blood samples and gene tests for FLCN were performed. BHD cases from other East Asian countries were reviewed. RESULTS: Two novel FLCN mutations were found in exon 9 and exon 7 respectively (c.946-947delAG and c.770-772delCCT). The cutaneous presentations were relatively rare in Asian countries. CONCLUSIONS: A definite diagnosis of BHD should only be made if a pathogenic FLCN germline mutation is detected. When cutaneous lesions are not found, search for mutations of FLCN gene should be also performed for patients with RCCs and pulmonary cysts, especially with a clear family history of RCCs or pulmonary cysts (pneumothoraces) in East Asian countries.