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Diastrophic Dwarfism

- Discussion:
    - rare type of skeletal dypslasia characterized by extreme short limb dwarfism, with specific hand, foot, and ear abnormalities;
          - micromelic short-limb dwarfism, cauliflower ears, scoliosis, hitchhiker thumbs, and clubfeet.
          - these individuals have extremely short stature, with a mean adult height of 118 cm;
    - condition was originally referred to as diastrophic dwarfism," which means "crooked or twisted" but was later changed
          to diastrophic dysplasia in 1977;
    - epiphyseal ossification is delayed, causing flattening & irregularity;
    - may be related to a defect in structure or synthesis of type II collagen in the physis;
    - transmitted as autosomal recessive trait (lesion lies at the distal end of the 5q chromosome);
    - some patients die in infancy but most have a normal life span;
    - intelligence is normal;

- Non Orthopaedic Manifestations:
    - 59% of affected infants have a cleft palate;
    - peculiar ear deformity, cauliflower ear, occurs later in childhood because of a cartilage abnormality;

- Orthopaedic Manifestations:
    - C spine:
            - cervical kyphosis
            - high incidence of quadriplegia;
    - hands:
            - hitchhiker thumb is distinctive feature of dysplasia and is caused by shortening of 1st metacarpal & radial subluxation of 1st MP 
    - spine:
            - surgical treatment is required for curves that continue to progress;
    - hip:
            - at hip, dislocation or DJD are common sequelae of coxa vara and incongruity;
            - hip flexion contracture may be seen in most patients;
    - foot:
            - rigid bilateral equinovarus deformities of feet are typical and are extremely resistant to cast treatment;
            - severe, rigid equinovarus deformity usually requires surgery;
            - symphalangism of the proximal interphalangeal joints of the fingers, and an abducted "hitchhiker's"  thumb are also present

Mutations in the diastrophic dysplasia sulfate transporter (DTDST) gene: correlation between sulfate transport activity and chondrodysplasia phenotype.

Disorders of the spine in diastrophic dwarfism.

The phenotipic variability of diastrophic dysplasia.

Diastrophic Dwarfism.

Lethal and non-lethal diastrophic dysplasia. A study of 14 Swedish cases.