MKX is a member of an Iroquois (IRX) family-related class of 'three-amino acid loop extension' (TALE) atypical homeobox proteins characterized by 3 additional amino acids in the loop region between helix I and helix II of the homeodomain.
Robertson NG, Khetarpal U, Gutiérrez-Espeleta GA, et al. (1994). "Isolation of novel and known genes from a human fetal cochlear cDNA library using subtractive hybridization and differential screening.". Genomics. 23 (1): 42–50. PMID7829101. doi:10.1006/geno.1994.1457.
Weinmann A, Galle PR, Teufel A (2005). "In silico characterization of an Iroquois family-related homeodomain protein.". Int. J. Mol. Med. 16 (3): 443–8. PMID16077953. doi:10.3892/ijmm.16.3.443.