AbstractMetacarpophalangeal pattern profile (MCPP) was determined in 49 radiographs of 40 patients with Rubinstein‐Taybi syndrome. Two recognizable hand profiles were seen, depending on the configuration of the thumb and on age. Patients with a straight thumb showed a short first proximal phalanx, and short third medial phalanx. Patients with a radially deviated thumb had a short first proximal phalanx. Depending on age, a relatively large (infancy) or markedly short (older patients) first distal phalanx was found. The similarity between the patients was high. A third group of patients did not show a particular hand profile, but only small hand bones. The pattern variability indices were high in all groups of patients.MCPP analysis in Rubinstein‐Taybi syndrome seems to be a powerful, but not pathognomonic, diagnostic t