Chronic Rhinosinusitis with Nasal Polyposis in an Adult with Homozygous Variants of Uncertain Significance in ABCA3 Gene

Abstract

IntroductionThe role of surfactant proteins in pulmonary diseases has been studied extensively. However, little is known about its contribution in diseases involving the nasal mucosa. Chronic rhinosinusitis with nasal polyps (CRSwNP) is a common disease characterized by persistent inflammation of the nasal passage and paranasal sinuses. We present a case of CRSwNP and interstitial lung disease (ILD) with variants of uncertain significance (VUS) in adenosine triphosphate binding cassette subfamily A member 3 (ABCA3) identified as potential genetic etiology. Case DescriptionPatient was a 42-year-old female with chronic obstructive pulmonary disease (COPD) with oxygen-dependance, bronchiectasis, history of hospitalization for bronchiolitis obliterans organizing pneumonia (BOOP) in infancy, who presented for evaluation of CRSwNP and anosmia. Nasal polyps were first discovered around three years of age, requiring more than 25 nasal polypectomies in her lifetime. Evaluation for cystic fibrosis during childhood was unremarkable. She reported only one episode of wheezing and denied aspirin sensitivity. Despite her significant history of BOOP in infancy, the patient remained without pulmonary infections until four years prior to presentation. Since then, she had two episodes of pneumonia and was diagnosed with COPD, leading to chronic oxygen use. Recent spirometry showed severe airflow obstruction, hyperinflation and decreased diffusing capacity for carbon monoxide. Chest CT revealed diffuse bronchiectasis, mucous plugging, and mild ground glass opacity. Patient had negative sweat test and normal alpha-1 antitrypsin level. Genetic testing with Invitae PCD panel and Neonatal Respiratory Distress panel revealed homozygous VUS [c.155C>T (p. Pro52Leu)] in ABCA3 gene. ConclusionOur patient had an atypical course of ILD, remaining asymptomatic most of her life, and CRSwNP. ABCA3 variants are associated with autosomal recessive pulmonary diseases, such as pulmonary surfactant metabolism dysfunction, pediatric ILD and pulmonary fibrosis1. Surfactant phospholipids are known to lower the surface tension in the alveoli, but they also decrease mucus viscosity and help to eliminate inhaled pathogens2,3,4. The pathophysiology of CRSwNP is unclear and the clinical phenotype of the disease varies widely. While the pathogenicity of the variant is not defined, this case raises a possibility that patient’s ABCA3 genotype may contribute to CRSwNP with recalcitrant nasal polyps.