JARID1C (UniProtKB/Swiss-Prot entry P41229) is a histone demethylase that specifically demethylates tri- and dimethylated Lys-4 of histone H3. It has no activity towards monomethylated H3K4, H3K9, H3K27, H3K36, H3K79 or H4K20. It is involved in transcriptional regulation and chromatin remodeling. JARID1C participates in transcriptional repression of neuronal genes by recruiting histone deacetylases and REST at neuron-restrictive silencer elements. Mutations in JARID1C have been associated with X-linked mental retardation