Nonsense mutations in folliculin presenting as isolated familial spontaneous pneumothorax in adults.
BACKGROUND
Approximately 10% of patients who have a spontaneous pneumothorax have a positive family history.


OBJECTIVE
We sought to identify DNA sequence variations that confer susceptibility to pneumothoraces.


METHODS
We collected 12 families that had at least 2 first-degree relatives with a spontaneous pneumothorax. All affected family members had no obvious stigmata of known genetic disorders associated with pneumothoraces. We used haplotype analysis, DNA sequencing, and restriction fragment analysis of mutations to evaluate the individuals in these families.


RESULTS
In 2 of the 12 families the disorder cosegregated with markers flanking a candidate locus, FLCN. Sequencing the linked alleles revealed 2 mutations predicted to introduce premature stop codons in 2 of the 12 families. Most mutations in FLCN cause a rare disease, Birt-Hogg-Dubé syndrome, characterized by autosomal dominant inheritance of multiple benign skin lesions, renal tumors, pulmonary blebs, and pneumothoraces. None of the family members with the nonsense mutations had the skin manifestations of Birt-Hogg-Dubé syndrome or renal cancer. Pathologic examination of lung tissue from three affected nonsmokers revealed blebs and underlying emphysema.


CONCLUSIONS
Isolated familial spontaneous pneumothorax can be caused by mutations of the FLCN gene. Because development of a pneumothorax and/or pulmonary blebs may be the earliest or the only clinical manifestation of FLCN mutations, pulmonologists should be alert to the contribution of this gene toward this familial form of emphysema.
Graham
Randall B
RB
Division of Pulmonary and Critical Care Medicine, Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-8591, USA.
Nolasco
Melissa
M
Peterlin
Borut
B
Garcia
Christine Kim
CK
D000328:Adult; D018389:Codon, Nonsense; D004970:Estrone / Q000235:genetics*; D005260:Female; D005799:Genes, Dominant; D006239:Haplotypes; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D011030:Pneumothorax / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D011506:Proteins / Q000235:genetics; D011518:Proto-Oncogene Proteins; D011656:Pulmonary Emphysema / Q000235:genetics; D017423:Sequence Analysis, RNA; D011795:Surveys and Questionnaires; D025521:Tumor Suppressor Proteins
D018389:Codon, Nonsense; C476078:FLCN protein, human; D011506:Proteins; D011518:Proto-Oncogene Proteins; D025521:Tumor Suppressor Proteins; D004970:Estrone