Background: MLASA (myopathy, lactate acidosis and sideroblastic anemia) is a rare autosomal recessive mitochondrial disorder, which affects oxidative phosphorylation and iron metabolism in skeletal muscle and bone marrow. Three genes have been identified so far, PUS1 is the most common, followed by YARS2 and MT-ATP6. We present a patient with a novel variant in YARS2 and a literature review. Methods: We report a 20-months-old girl with ptosis and low birth weight. She presented with delayed motor milestones and bulbar weakness with feeding difficulties. She had mild anemia and elevated lactate, echocardiogram revealed a mild to moderate left ventricular hypertrophy without LVOT obstruction. Results: Genetic testing showed two heterozygous variants in YARS2. The maternal one (c.948G>T, p. Arg316Ser) has been reported previously in a compound heterozygous state, while the paternal one (c.917T>C, p.Phe306Ser) has not been previously described. Genetic findings were supported by enzyme activities, which showed reduced complex I+III and complex IV activities and reduced cytochrome oxidase (COX). Conclusions: In this case report we describe a 20-months-old girl with clinical features of MLASA. A novel variant in the YARS2 gene was found, pathogenicity could be proven with clinical phenotype and enzyme activity testing.