- Discussion:
    - this disorder is frequently confused with metatrophic dysplasia;
    - characterized by disproportionate short trunk dwarfism, kyphoscliosis, and joint stiffness, and contractures of the hands;
    - assessment of atlantoaxial instability is essential;
    - major orthopaedic deformity is limited joint motion and contractures;
    - these patients are predisposed to early osteoarthritis;
    - may be caused by a mutation in type II collagen