Purpose or Case Report: Filamin A (FLNA) is a widely expressed X-linked dominant gene that encodes Filamin A, a protein that crosslinks actin filaments and plays a crucial role in the structure of the cell cytoskeleton. With such a broad role, FLNA mutations are especially consequential and can result in cardiovascular malformations, intellectual disability, skeletal dysplasia, and neuronal migration abnormalities. Additionally, recent literature has linked FLNA mutation to pediatric-onset interstitial lung disease.
A three-month-old female with a history of atrial septal defect, patent ductus arteriosus, pulmonary valve dysplasia, micrognathia, and recent hospitalization for parainfluenza infection causing respiratory failure presented to the emergency department with worsening hypoxemia and respiratory distress. Initial chest radiograph demonstrated an interval increase in bilateral patchy opacifications suggestive of worsening multifocal infection. The patient was subsequently admitted. The patient’s clinical status failed to improve after multiple days of admission. A non-contrast CT study of the chest revealed multiple regions of air trapping, atelectasis, coarsened interstitial markings, and diffuse septal thickening, differential diagnosis included interstitial lung disease versus congenital alveolar abnormality. Of note, MR imaging of the brain obtained showed diffuse nodularity along the subependymal lining of the lateral ventricles and temporal horns, compatible with gray matter heterotopia. This prompted genetic testing which revealed Filamin A deficiency.
Filamin A mutation typically presents radiographically with hyperinflation of the lungs with scattered atelectasis, which can be complicated by concomitant pneumonia. This appearance can mimic pulmonary emphysema and bronchopulmonary dysplasia. Cardiac anomalies are a common manifestation of the mutation; notably, our patient had a history of a dysplastic pulmonary valve, ASD and PDA. CT imaging patterns vary and can present as a combination of cystic and diffuse ground-glass changes, hyperinflation, and emphysema. After extensive consultation, our patient transitioned to palliative care and ultimately passed away at 5 months of age. Maintaining a high index of suspicion for this rare but important entity is crucial to accurately diagnosing this inherited mutation, treating affected patients appropriately, and providing patients and their families with essential information regarding prognosis and inheritance patterns.
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