As observed in hyperplastic MG thymuses [85], miR-125a-5p was found to be markedly overexpressed in MG samples, and its abnormal expression was functionally linked to the down-regulation of FOXP3, the master transcription factor implicated in Treg generation and functionality, suggesting a contribution of this miRNA to Treg deficiency in MG thymomas. This evidence concerns the gene FOXP3 and myasthenia gravis.