Pulmonary alveolar microlithiasis: A case report with a novel mutation in the SLC34A2 gene and review of the literature

Pulmonary alveolar microlithiasis (PAM) is a rare autosomal recessive genetic disease characterized by intraalveolar psammomatous calcium phosphate deposition. Patients with PAM are often asymptomatic until the third or fourth decade, when they most frequently develop symptoms including dyspnea, and dry cough. Only one-third of the reported patients are under twenty years of age and manifestation during infancy is extremely rare. We present a case of an infant with chronic respiratory symptoms including tachypnea, retractions, crackles, and hypoxia since 2 months of age. Chest computed topography at age 8 months showed bilateral diffuse ground glass opacities and septal thickening suggestive of interstitial lung disease. Lung biopsy showed numerous intraalveolar calcified laminated structures consistent with PAM. Genetic testing confirmed the diagnosis, demonstrating a previously unreported mutation c.524-18_559del in the SLC34A2 gene. Keywords: Pulmonary alveolar microlithiasis, Solute family member