The many similarities of FNIP1 and Tsc1 as Hsp90 co-chaperones, coupled with the similar clinical phenotypes of BHD and TSC syndromes and unique identification of sporadic AML in this patient with BHD prompted us to investigate the chaperoning of the mutant FLCN protein that results from the germline mutation of this patient. The gene discussed is FLCN; the disease is Birt-Hogg-Dube syndrome.