X-linked mental retardation with seizures and carrier manifestations is caused by a mutation in the creatine-transporter gene (SLC6A8) located in Xq28. - Hahn,K.A.; Salomons,G.S.; Tackels-Horne,D.; Wood,T.C.; Taylor,H.A.; Schroer,R.J. (Am J Hum Genet, 2002)