Genes of the Rhox gene family from a gene cluster on the mammalian X chromosome. The mouse Rhox cluster has 32 genes; the human cluster has three genes: RHOXF1, RHOXF2 and RHOXF2B. The latter two are extremely closely related and most likely a very recent tandem duplication. It is unclear if all three genes are functional. The Rhox genes are not present in Drosophila or amphioxus.

The Rhox cluster genes targeted for H1-mediated transcriptional repression are also subject to another DNA methylation-regulated process: Xp imprinting. Rhox gene cluster is a major target of H1-mediated transcriptional repression in ES cells and that H1 is a candidate to have a role in Xp imprinting. The rhox homeobox gene cluster is imprinted and selectively targeted for regulation by histone h1 and DNA methylation.