SRY-related HMG-box (SOX) genes encode a family of DNA-binding proteins containing a 79-amino acid HMG (high mobility group) domain that shares at least 50 % sequence identity with the DNA-binding HMG box of the SRY protein (MIM 480000). SOX proteins are divided into 6 subgroups based on sequence similarity within and outside of the HMG domain. For additional background information on SOX genes, see SOX1 (MIM 602148).,SOX21,SOX25,Epigenetics & Nuclear Signaling,Transcription Factors,Neuroscience,SOX21