Regressive spondylometaphyseal dysplasia

A rare, primary bone dysplasia characterized by mild short stature, rhizomelic shortening of the arms and legs, bowing of long bones with widened and irregular metaphyses, thoracolumbar kyphosis, and metacarpal shortening. A marked improvement of the radiologic skeletal features is typical. Pelger-Huet anomaly (i.e. dumbbell shape bilobed nuclei of neutrophils) is a characteristic hematological feature of this disease.