Delineation of the Costello syndrome.

We present a 15-year-old girl with mental retardation, short stature, coarse face, unusually thick, loose skin of the hands and feet, deep plantar and palmar creases, and nasal papillomata. Her history and physical findings are compared to those of 2 children initially reported by Costello and to 1 child recently reported by Der Kaloustian et al.