ENOrphanet Journal of Rare Diseases | Preliminary Study on FLNA Gene Variants and Emphysema Frequency and Characteristics in Adults
Date: October 01, 2023
Classification: Frontiers
Recommend:
This study systematically evaluates the emphysema incidence in adults with FLNA pathogenic variants for the first time, revealing clinical features and providing new directions for early screening of rare hereditary lung diseases.
Literature Overview
The article 'Frequency and characteristics of emphysema in adults with FLNA variants: a single-center study', published in Orphanet Journal of Rare Diseases, reviews the potential association between FLNA gene pathogenic variants and adult emphysema. The research team at Lille University Hospital, France conducted a cross-sectional single-center study, analyzing emphysema frequency and characteristics in 10 adult females with FLNA pathogenic variants through clinical data collection, chest CT scans, and pulmonary function tests. Study results showed a 70% emphysema prevalence rate, with 57.1% classified as 'unexplained emphysema' not attributable to environmental exposures. Pulmonary function tests demonstrated reduced diffusion capacity and small airway dysfunction.
Background Knowledge
The FLNA gene (Filamin A) encodes an actin-binding protein involved in cytoskeletal organization. FLNA pathogenic variants are categorized into loss-of-function and gain-of-function types, associated with various congenital disorders such as periventricular nodular heterotopia (PVNH), cardiovascular abnormalities, and thoracic aortic dilatation. Existing literature documents childhood pulmonary manifestations including neonatal respiratory failure, congenital emphysema, and interstitial lung disease, but adult emphysema reports remain limited. Previous findings by researchers identified female emphysema cases in two families without smoking/environmental exposure explanations, suggesting FLNA as a potential genetic factor. This study aims to verify this hypothesis and assess the prevalence of emphysema in FLNA variant carriers. Key challenges include distinguishing environmental from hereditary emphysema, standardizing pulmonary function testing, and ensuring accuracy of small airway assessments. The research fills knowledge gaps in adult rare hereditary lung diseases and establishes foundations for broader future studies.
Methods and Experiments
This cross-sectional single-center prospective study was conducted at Lille University Hospital, France. Ten adult female patients with FLNA pathogenic variants were selected through the French rare disease database BaMaRa®. Exclusion criteria included inability to provide informed consent, guardianship, pregnancy, or lactation. All participants underwent medical examinations, non-contrast chest CT scans, and pulmonary function tests (PFT) including spirometry, body plethysmography, diffusing capacity for carbon monoxide (DLCO), and impulse oscillometry (IOS). Emphysema was defined as low attenuation areas using visual assessment and automated quantitative analysis (voxel count with density < -950 HU). PTPN6 gene mutations and α1-antitrypsin deficiency were also screened to exclude other hereditary emphysema causes.
Key Findings
Significance and Future Directions
This is the first systematic evaluation of FLNA pathogenic variants' association with emphysema, providing preliminary evidence supporting the necessity of multicenter studies. The findings emphasize pulmonary function monitoring and respiratory symptom management in FLNA mutation carriers, particularly highlighting emphysema screening. Future studies could expand to larger cohorts and employ animal models to validate FLNA's role in lung development and airway integrity.
Conclusion
This preliminary study reveals a significant association between FLNA pathogenic variants and high emphysema prevalence in adult females, where most cases cannot be explained by conventional risk factors. The findings suggest genetic factors should be considered in evaluating unexplained emphysema, particularly in female patients. Pulmonary function parameters like reduced DLCO and small airway dysfunction may serve as auxiliary indicators for early emphysema screening. Despite small sample size and single-center design, these results provide strong justification for larger multicenter studies that could potentially influence genetic screening guidelines and clinical management strategies for emphysema.
