Therefore, based on the ACMG classification10 we classified the FARS2 variant as a variant of unknown significance (VUS), as it has not previously been related to disease, it is classified in ClinVar database as a VUS, it is located on an amino acid residue that is not fully conserved through evolution (Supplementary Fig. 2), and the previously FARS2-associated phenotypes (spastic paraplegia and combined oxidative phosphorylation deficiency) are not related to arthritis. This evidence concerns the gene FARS2 and Spastic paraplegia.