X-Linked Intellectual Disability-Limb Spasticity-Retinal Dystrophy-Diabetes Insipidus Syndrome An important gene associated with X-Linked Intellectual Disability-Limb Spasticity-Retinal Dystrophy-Diabetes Insipidus Syndrome is PRPS1 (Phosphoribosyl Pyrophosphate Synthetase 1). Affiliated tissues include eye and brain, and related phenotypes are intellectual disability, profound and hypertelorism