Case Report: Novel compound heterozygous mutations in SLC34A2 gene: a case of pulmonary alveolar microlithiasis in a child.

Pulmonary alveolar microlithiasis (PAM), a rare disorder caused by SLC34A2 mutations, demonstrates clinical-radiological discordance. Pediatric cases face heightened diagnostic challenges; nonspecific presentations often result in misattribution to recurrent pneumonia or delayed diagnosis, especially in children ≤5 years. We present a case of a 3-year-old girl hospitalized for persistent cough (11-day duration) and intermittent fever (9-day history). Her recurrent productive cough had been misattributed to recurrent pneumonia in prior healthcare encounters. Diagnostic imaging revealed extensive calcifications in the left lower lobe on chest CT, accompanied by small clustered onion-like calcifications in bronchoalveolar lavage fluid(BALF). Sputum culture identified Haemophilus influenzae infection. Genetic analysis revealed novel compound heterozygous variants in SLC34A2: c.524-1G>C (IVS5) inherited maternally and c.910A>T (EX8) of paternal origin. The patient was diagnosed with PAM complicated by Haemophilus influenzae pneumonia. These compound heterozygous SLC34A2 variants represent previously unreported pathogenic mutations. We conclude that heightened attention should be directed toward detecting calcifications on mediastinal and bone windows during pediatric imaging examinations. Genetic analysis plays a pivotal role in diagnosing rare childhood disorders and may emerge as the primary diagnostic modality for PAM in pediatric populations.