Coffin-Lowry syndrome (CLS) is a syndromic form of X-linked mental retardation, which is characterized in male patients by psychomotor and growth retardation and various skeletal anomalies. Typical facial changes and specific clinical and radiological signs in the hand are useful aids in the diagnosis. Mutations in the RSK2 (RPS6KA3) gene cause CLS. The RPS6KA3 gene encodes RSK2 that is involved with signaling within cells.
