OSLAM syndrome is characterised by the association of osteosarcoma, limb anomalies (clinodactyly with brachymesophalangy, bilateral radioulnar synostosis and absence of one digital ray of the foot) and red cell macrocytosis without anaemia.

Clinodactyly refers to a bending or curvature of the fifth finger in the radial direction (i.e., towards the 4th finger).