Researchers have identified a novel missense mutation in tyrosyl-tRNA synthetase (YARS c.499C>A, p.Pro167Thr) that causes a severe recessive disorder in affected individuals. The report includes detailed clinical characterization of seven related Amish children who were homozygous for the variant. The children all exhibited poor growth, developmental delay, abnormal brain white matter, hearing loss, involuntary eye movements, progressive cholestatic liver disease, pancreatic insufficiency, hypoglycemia, anemia, intermittent excess of protein in urine, recurrent bloodstream infections, and chronic pulmonary disease.