Methionyl-tRNA synthetase novel mutation causes pulmonary alveolar proteinosis

The methionyl-tRNA synthetase (MARS) mutation is a very rare cause of congenital pulmonary alveolar proteinosis. We report a 6-month-old boy born with symmetrical intrauterine growth retardation presented with unexplained persistent tachypnea and hypoxemia associated with severe failure to thrive, anemia, hypoalbuminemia and hepatomegaly. Detailed pulmonary investigations including computed tomography chest scan, bronchoscopy and bronchoalveolar lavage revealed pulmonary alveolar proteinosis. Whole exome sequencing identified a homozygous novel variant in the MARS gene, c.854T>C p.(Ile285Thr).