AARS2 and mitochondrial complex IV deficiency, nuclear-type: Clinical exome sequencing identified two novel variants, NM_020745:c.2864G>A (p.W955*) and NM_020745:c.1036C>A (p.P346T, p.P346Wfs*18), in AARS2. Histopathological and biochemical studies on muscle biopsy revealed mitochondrial disorder with cytochrome C oxidase (COX) deficiency.