RPS6KA3 and Rubinstein-Taybi syndrome: On the other hand, since VRK1 activates CREB, mutations in VRK1 may cause neurological phenotypes by disrupting the CREB signaling pathway, as had been shown mutations in RSK2 (CREB kinase) and CREBBP (CREB- binding protein) cause neurological diseases Coffin Lowry syndrome and Rubinstein Taybi syndrome, respectively [12].