- Mutations in the JARID1C gene, which is involved in transcriptional regulation and chromatin remodeling, cause X-linked mental retardation. Jensen, L.R., Amende, M., Gurok, U., Moser, B., Gimmel, V., Tzschach, A., Janecke, A.R., Tariverdian, G., Chelly, J., Fryns, J.P., Van Esch, H., Kleefstra, T., Hamel, B., Moraine, C., Gecz, J., Turner, G., Reinhardt, R., Kalscheuer, V.M., Ropers, H.H., Lenzner, S. Am. J. Hum. Genet. (2005)