A rare skeletal disease with characteristics of symmetric shortening of the middle segments of limbs and short stature. It has been described in five families. In the upper limbs, the ulnae are very short, and the radii are bowed. The distal humerus has a dumbbell shape. The hands show progressive flexion contractures of the proximal interphalangeal joints. In the lower limbs, feet are fixed in plantar flexion so that the patients walk on their toe tips. All affected patients have normal craniofacial features and intelligence. Two micro duplications have been identified on chromosome 2 (2q31.1-q31.2), separated by a segment of normal copy number. In all families, the condition is transmitted as an autosomal dominant trait.