MedGen

Primary spontaneous pneumothorax (PSP) is a condition in which air enters the pleural space and causes secondary lung collapse. It is mostly sporadic but also occurs in families. It is associated with bullae in the lungs of most patients (summary by Painter et al., 2005). Birt-Hogg-Dube syndrome (BHD; 135150), which is characterized by spontaneous pneumothorax as well as by fibrofolliculomas of the skin and increased risk of renal and colonic tumors, is also caused by mutation in the FLCN gene. Gunji et al. (2007) suggested that isolated primary spontaneous pneumothorax associated with FLCN mutations may be part of the clinical spectrum of BHD, showing incomplete disease penetrance. Spontaneous pneumothorax is a complication of certain heritable disorders of connective tissue, particularly the Marfan syndrome (154700) and the Ehlers-Danlos syndrome (see, e.g., 130000). Pulmonary bullae can also occur with alpha-1-antitrypsin deficiency (613490). [from OMIM]

The clinical characteristics of Birt-Hogg-Dubé syndrome (BHDS) include cutaneous manifestations (fibrofolliculomas, acrochordons, angiofibromas, oral papules, cutaneous collagenomas, and epidermal cysts), pulmonary cysts/history of pneumothorax, and various types of renal tumors. Disease severity can vary significantly even within the same family. Skin lesions typically appear between the second and fourth decades of life and typically increase in size and number with age. Lung cysts are often bilateral and multifocal; most individuals are asymptomatic but at high risk for spontaneous pneumothorax. Individuals with BHDS are at a sevenfold increased risk for renal tumors that can be bilateral and multifocal; median age of renal tumor diagnosis is 48 years. The most common renal tumors are a hybrid of oncocytoma and chromophobe histologic cell types (oncocytic hybrid tumor) and chromophobe histologic cell types. Some families have renal tumor(s) and/or spontaneous pneumothorax without cutaneous manifestations. [from GeneReviews]