Fig. 3

Schematic diagram and molecular model of the VARS2 gene. a VARS2 sequence alignment among representative species around the sites of the missense mutations (p.H215Y and p.M452 V). b Homology model of VARS2 (partial amino acids from positions 129 to 1079). Different colors represent different functional regions: the compound heterozygous mutation (p.His215 and p.Met452) is shown in red, the valine-tRNA ligase region in blue, the ATP biding site in yellow, the tRNA-synthetase domain in green and the anticodon binding domain in orange. c Schematic representation of the VARS2 protein. The novel compound heterozygous mutation reported here coincides with the tRNA-synthetase domain