YARS1 and Charcot-Marie-Tooth disease: Interestingly, several independent studies demonstrated in vitro and/or in vivo that loss of aminoacylation activity is not a common trait among the CMT-causing mutations in GARS1, YARS1, HARS1 and AARS1, implicating another function involved in the pathology (Figure 1) [18,19,21,28,29,30,31,32,33,34,35,36].