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Familial spontaneous pneumothorax is a rare, genetic pulmonary disease characterized by the uni- or bilateral accumulation of air in the pleural cavity in persons with a positive family history and no underlying lung disease or previous chest trauma. Patients typically present dyspnea associated with acute onset of sharp and steady pleutiric chest pain of variable severity (which resolves within 24h even though pneumothorax is still present). Reflex tachycardia and/or respiratory or circulatory compromise may be observed. Other syndromes (e.g. Birt-Hogg-Dube, Marfan or Ehlers-Danlos syndromes) may be associated.
Features include: Spontaneous pneumothorax.
Organ System | Phenotype Count | Example Features |
|---|---|---|
Lungs and breathing | 1 | Spontaneous pneumothorax |
FLCN encodes folliculin (579 aa). Multi-functional protein, involved in both the cellular response to amino acid availability and in the regulation of glycolysis. Highest expression in Brain Cerebellum (123.5 TPM) and Cervix Ectocervix (117.5 TPM).
Familial spontaneous pneumothorax is associated with mutations in the FLCN gene on chromosome 17.
FLCN is classified as a druggable target (Clinically Actionable category) with score 1.5.
Clinical diagnostic criteria for the diagnosis of Birt-Hogg-Dub syndrome (BHDS) have been published .
BHDS should be suspected in individuals with any of the following clinical findings and/or family history.
Clinical findings
• Pulmonary
Primary spontaneous pneumothorax
No approved treatments are currently available for familial spontaneous pneumothorax. The disease remains an area of unmet medical need.
The following recommendations are based on published practice guidelines . Evaluations Following Initial Diagnosis To establish the extent of disease and needs in an individual diagnosed with BHDS, the evaluations summarized (if not performed as part of the evaluation that led to the diagnosis) are recommended. Table 4. Birt-Hogg-Dub Syndrome: Recommended Evaluations Following Initial Diagnosis
The recommendations summarized in are based on the current clinical practice guidelines .
Table 6.
Birt-Hogg-Dub Syndrome: Recommended Surveillance
System/Concern | Evaluation | Frequency
| • Assess for pulmonary signs/symptoms of lung cysts/ pneumothorax.
7 clinical trials registered, 3 recruiting. Interventions under study include other interventions, procedural interventions, and medical devices. Pipeline includes 1 PHASE1, 5 NA. Research is primarily sponsored by academic and government institutions.
NCT ID | Title | Phase | Sponsor | Status |
|---|---|---|---|---|
[NCT06644820](https://clinicaltrials.gov/study/NCT06644820) |
Data assembled from 8 of 12 sources · Last updated Sep 18, 2026, 11:51 PM UTC
Online Mendelian Inheritance in Man
European rare disease database
Genetic and Rare Diseases Info Center
The clinical characteristics of Birt-Hogg-Dub syndrome (BHDS) include fibrofolliculomas (specific cutaneous lesions), pulmonary cysts/ history of pneumothorax, and various types of renal tumors. Intra- as well as interfamilial variation in disease severity can be significant. To date, more than 1,000 individuals have been identified with a pathogenic variant in FLCN. The following description of the phenotypic features associated with this condition is based on these reports. Table 2. Birt-Hogg-Dub Syndrome: Frequency of Select Features
Feature | % of Persons w/Feature(lifetime risk) | Comment |
|---|---|---|
Cutaneous manifestations (e.g., fibrofolliculoma, acrochordons) | 87%-97%1 | Cutaneous manifestations are unusual in persons age 20 yrs. |
Pulmonary cysts | 70%-85%2 | The age when cysts start to appear is unknown; childhood onset is likely. |
Spontaneous recurrent pneumothorax | 24%-48%3 | — |
Renal cell carcinoma | 15%-30%4,5 | 1. , 2. 3. 4. 5. Individuals with BHDS usually present with multiple small skin-colored, opaque, whitish or yellowish dome-shaped papules known as fibrofolliculomas. These noncancerous skin lesions start to appear between the second and fourth decade of life. |
Source: GeneReviews — "Birt-Hogg-Dub Syndrome"
No genotype-phenotype correlations for FLCN have been confirmed. The following correlations are preliminary:
c.1285delC or c.1285dupC. A lower renal tumor frequency was observed in individuals with either of the two most common FLCN pathogenic variants in a study including 50 families .
c.1285dupC. Analysis of a subset of 51 families with BHDS demonstrated a significantly higher risk of colorectal neoplasia in those with the common FLCN pathogenic variant c.1285dupC compared to those with the c.610delGCinsTA pathogenic variant .
Source: GeneReviews — "Birt-Hogg-Dub Syndrome"
Based on the three major clinical manifestations, penetrance of BHDS is considered to be very high. Up to 97% of individuals with a heterozygous germline FLCN pathogenic variant develop at least one feature of BHDS during their lifetime .
Source: GeneReviews — "Birt-Hogg-Dub Syndrome"
Multiple lung cysts (particular in the lower lung zone) without known cause
• Renal
Early-onset renal cell cancer (age 50 years)
Multifocal or bilateral renal cell cancer or oncocytoma
≥2 family members with renal cancer
Cutaneous. Multiple fibrofolliculomas/trichodiscomas
Family history is consistent with autosomal dominant inheritance (e.g., affected males and females in multiple generations). Absence of a known family history does not preclude the diagnosis.
Establishing the Diagnosis
The cli...
Source: GeneReviews — "Birt-Hogg-Dub Syndrome"
Genes of interest in the differential diagnosis of Birt-Hogg-Dub syndrome (BHDS) are listed in . Table 3. Genes of Interest in the Differential Diagnosis of Birt-Hogg-Dub Syndrome
Phenotype | Gene(s) | Disorder | MOI | Key Features of Disorder |
|---|---|---|---|---|
Cutaneous manifestations1 | CYLD2 | Multiple familial trichoepithelioma (See CYLD Cutaneous Syndrome.) | AD | Cutaneous manifestations may appear similar on clinical exam. |
Multiple endocrine neoplasia type 1 | AD | Facial angiofibromas collagenomas | Ependymomas, meningiomas | — |
PTEN | Cowden syndrome (See PTEN Hamartoma Tumor Syndrome.) | AD | Uterine renal cancers | Trichilemmomas, acral keratoses (must be distinguished histopathologically), mucosal lesions Lung cysts /or pneumothorax |
Cystic fibrosis | AR | Only lung cysts | Progressive obstructive lung disease w/bronchiectasis inflammation COL3A1 | — |
Vascular Ehlers-Danlos syndrome | AD(AR) | Only lung cysts | Spontaneous pneumothoraces may be 1st significant presenting feature; hemothorax, hemopneumothorax, pulmonary blebs, cystic lesions, hemorrhagic or fibrous nodules FBN1 | — |
FBN1-related Marfan syndrome | AD | Lung cysts spontaneous pneumothorax | Lung bullae typically in upper lobes SERPINA1 | — |
Alpha-1 antitrypsin deficiency | See footnote 3. | Only lung cysts | Chronic obstructive pulmonary disease; emphysema, sometimes w/bronchiectasis TSC1 TSC2 | — |
Tuberous sclerosis complex | AD | Lung cysts skin papules (facial angiofibromas) | Additional skin lesions: hypomelanotic macules, confetti skin lesions, shagreen patches, fibrous cephalic plaques, ungual fibromas; pulmonary lymphangioleiomyomatosis Renal cancer4 | BAP1 |
BAP1 tumor predisposition syndrome | AD | Various types of RCC, cutaneous melanoma | Mesothelioma, uveal melanoma FH | — |
FH tumor predisposition syndrome | AD | Various types of renal cancer, cutaneous leiomyoma, uterine fibroids | Renal tumors are usually solitary less likely to be oncocytoma or chromophobe type. MAX SDHA SDHAF2 SDHB SDHC SDHD TMEM127 | — |
Hereditary paraganglioma-pheochromocytoma syndromes | AD | risk for paragangliomas, pheochromocytomas, RCCs incl oncocytic renal tumors | Gastrointestinal stromal tumors | — |
MET | Hereditary papillary renal cancer (OMIM 605074) | AD | Bilateral multifocal type 1 papillary RCC | — |
PTEN | Cowden syndrome (See PTEN Hamartoma Tumor Syndrome.) | AD | Uterine renal cancers, skin papules | Benign hamartomas risks of breast, thyroid, other cancers; other dermatologic features (e.g., lipomas, trichilemmomas, oral papillomas, penile freckling) VHL |
Von Hippel-Lindau syndrome | AD | Bilateral multifocal clear cell RCC; risk for pheochromocytoma | risk for CNS hemangioblastoma, retinal angioma, end... | — |
Source: GeneReviews — "Birt-Hogg-Dub Syndrome"
Genetic testing for FLCN is available. Testing is considered confirmatory for diagnosis.
Biomarker and diagnostic research for familial spontaneous pneumothorax has been reported in the published literature.
System/Concern | Evaluation | Comment |
|---|---|---|
Integument | Detailed dermatologic exam | Beginning at age 20 yrs |
Pulmonary | Discuss avoiding activities that might pneumothorax risk (e.g., working as a pilot, flying in unpressurized aircraft, diving) | HRCT or CT of chest for visualization of pulmonary cysts evidence for pneumothorax |
Renal | Abdominal/pelvic MRI to screen for renal tumor(s) | Beginning at age 20 yrs |
Genetic counseling | By genetics professionals1 | To obtain a pedigree inform affected persons their families re nature, MOI, implications of BHDS to facilitate medical personal decision making BHDS = Birt-Hogg-Dub syndrome; HRCT = high-resolution computed tomography; MOI = mode of inheritance 1. |
Birt-Hogg-Dub Syndrome: Treatment of Manifestations Manifestation/Concern | Treatment | Considerations/Other |
Pneumothorax | Standard treatment per pulmonologist | Surgical intervention should be considered for recurrent pneumothoraces. Renal tumors; At least 1 renal tumor ≥3.0 cm: Eval by urologic surgeon. Nephron-sparing surgery of tumors should be used whenever possible. |
Birt-Hogg-Dub Syndrome: Recommended Surveillance System/Concern | Evaluation | Frequency Lung cysts/ Pneumothoraces; Discuss avoidance of activities that might pneumothorax risk (e.g., working as a pilot, flying in unpressurized aircraft, diving) |
Source: GeneReviews — "Birt-Hogg-Dub Syndrome"
Avoid the following:
Cigarette smoking
High ambient pressures, which may precipitate spontaneous pneumothorax. Air travel increases pneumothorax risk .
Radiation exposure
Source: GeneReviews — "Birt-Hogg-Dub Syndrome"
Search ClinicalTrials.gov in the US and EU Clinical Trials Register in Europe for access to information on clinical studies for a wide range of diseases and conditions. Note: There may not be clinical trials for this disorder.
Source: GeneReviews — "Birt-Hogg-Dub Syndrome"
7 trials found
Discuss avoidance of activities that might pneumothorax risk (e.g., working as a pilot, flying in unpressurized aircraft, diving)
|
Lung CT | • Only as needed
No routine screening in those w/o signs/symptoms to avoid cumulative radiation exposure
| • Abdominal/pelvic MRI is optimal.1
Abdominal/pelvic CT w/contrast (if MRI is not an option)2
| • Annually starting at age 20 yrs3
Continue annually in those w/suspicious lesion(s) (1.0 cm in diameter, indeterminate lesion, or complex cysts)
In those w/o family history of renal tumors, after 2-3 consecutive normal MRIs, continue screening every 2 yrs4
1. The use of renal ultrasound examination is helpful in further characterization of kidney lesions but should not be used as a primary screening modality due to its unreliability in detecting tumors 3 cm in diameter . Renal ultrasound can be considered in the 12-month interval between MRI screenings.
2. The long-term effect of cumulative radiation exposure in individuals with BHDS is unknown and has not been studied.
3. Surveillance can start earlier in those with a family history of renal tumors before age 30 years.
Source: GeneReviews — "Birt-Hogg-Dub Syndrome"
Clinical Characteristics and Outcome of Patients Xith Spontaneous Pneumothorax |
— |
Sohag University |
RECRUITING |
[NCT06053476](https://clinicaltrials.gov/study/NCT06053476) | Optimal Postoperative Chest Tube and Pain Management in Patients Surgically Treated for Primary Spontaneous Pneumothorax (Pneumotrial) | NA | Maxima Medical Center | RECRUITING |
[NCT06471608](https://clinicaltrials.gov/study/NCT06471608) | Impact of Ambulatory Management for Primary Spontaneous Pneumothorax in the Emergency Department on Quality of Life | NA | University Hospital, Strasbourg, France | NOT_YET_RECRUITING |
[NCT07331805](https://clinicaltrials.gov/study/NCT07331805) | Conservative Management in Primary Spontaneous Pneumothorax: a Multicenter Randomized Non-inferiority Study | NA | Corporacion Parc Tauli | NOT_YET_RECRUITING |
[NCT06413966](https://clinicaltrials.gov/study/NCT06413966) | Study Compares Pneumothorax Recurrence: Absorbable Mesh vs. Pleurectomy in Primary Spontaneous Pneumothorax. | NA | Chiang Mai University | UNKNOWN |
156 publications have been identified in PubMed for familial spontaneous pneumothorax. Research spans Clinical Trial Publication (32%), Epidemiology / Natural History (20%), and Case Report / Case Series (18%).
Research Type | Count | % of Total |
|---|---|---|
Clinical study results | 48 | 32% |
Disease patterns and progression | 31 | 20% |
Patient case studies | 27 | 18% |
Research summaries | 25 | 16% |
Testing and diagnosis research | 9 | 6% |
Other research | 6 | 4% |
New treatment approaches | 4 | 3% |
Laboratory research | 2 | 1% |
Pulle MV (2026). [PMID: 41499289](https://pubmed.ncbi.nlm.nih.gov/41499289/). *Asian Cardiovasc Thorac Ann*. [Review / Meta-Analysis]
Alp AS (2026). [PMID: 41527407](https://pubmed.ncbi.nlm.nih.gov/41527407/). *Turk Gogus Kalp Damar Cerrahisi Derg*. [Epidemiology / Natural History]
Napolitano AG (2026). [PMID: 42188352](https://pubmed.ncbi.nlm.nih.gov/42188352/). *J Pers Med*. [Epidemiology / Natural History]
Arai W (2026). [PMID: 41492809](https://pubmed.ncbi.nlm.nih.gov/41492809/). *Pathol Int*. [Case Report / Case Series]
Güneş SG (2026). [PMID: 42032552](https://pubmed.ncbi.nlm.nih.gov/42032552/). *BMC Pulm Med*. [Epidemiology / Natural History]
Chen X (2026). [PMID: 41905781](https://pubmed.ncbi.nlm.nih.gov/41905781/). *Ther Adv Respir Dis*. [Review / Meta-Analysis]
Jouneau S (2026). [PMID: 42120265](https://pubmed.ncbi.nlm.nih.gov/42120265/). *Rev Mal Respir*. [Review / Meta-Analysis]
Veale N (2026). [PMID: 41192553](https://pubmed.ncbi.nlm.nih.gov/41192553/). *Chest*. [Clinical Trial Publication]
Siu H (2026). [PMID: 41837180](https://pubmed.ncbi.nlm.nih.gov/41837180/). *Respirol Case Rep*. [Clinical Trial Publication]
Engwall-Gill AJ (2026). [PMID: 42167983](https://pubmed.ncbi.nlm.nih.gov/42167983/). *J Surg Res*. [Epidemiology / Natural History]
AI-curated news mentioning familial spontaneous pneumothorax
Updated May 14, 2026
A case report details pulmonary aspergillosis complicated by recurrent pneumothorax in a patient with HIV. This study highlights the complexities of managing co-infections in immunocompromised individuals.