We report a 2-year-old male infant with the Coffin-Lowry syndrome, and describe the change in his clinical and radiographic manifestations during the first 2 years of life. Review of published cases of the Coffin-Lowry syndrome indicates that these manifestations are progressive, and that all of the associated characteristics may not be apparent in early childhood. The importance of continued evaluations of these patients and examination of relatives for mild manifestations is emphasized.