Updated: 10/11/2016

Diastrophic Dysplasia

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Questions
4 4
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Evidence
4 4
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Videos
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https://upload.orthobullets.com/topic/4097/images/Clinical photo_moved.jpg
https://upload.orthobullets.com/topic/4097/images/cauliflower ear - colorado_moved.jpg
https://upload.orthobullets.com/topic/4097/images/hitchhikers thumb - colorado_moved.jpg
https://upload.orthobullets.com/topic/4097/images/Cervical kyphosis_moved.jpg
https://upload.orthobullets.com/topic/4097/images/Clubfeet_moved.jpg
Introduction
  • A form of short-limbed dwarfism caused by failure of formation of secondary ossification center (epiphysis)
    • associated with progressive deformity
  • Epidemiology
    • more common Finland
    • rare in rest of world
  • Genetics
    • autosomal recessive
    • mutation in DTDST gene (SLC26A2) on chromosome 5 
      • encodes for sulfate transporter protein q q    
      • mutation is present in 1 in 70 Finnish citizens
      • leads to undersulfation of cartilage proteoglycan
Presentation
  • Physical exam and syndrome features
    • short stature ("twisted dwarf")
      • rhizomelic shortening
    • cleft palate (60%)
    • cauliflower ears (80%) 
    • poorly developed UE
    • hitchhikers thumb  q 
    • thoracolumbar scoliosis
    • severe cervical kyphosis 
    • hip and knee contractures
    • genu valgum
    • skewfoot (serpentine or Z foot)
      • tarsometatarsal adductus and valgus hindfoot
    • rigid clubfeet (equinocavovarus) 
Imaging
  • Radiographs
    • recommended views
      • AP and lateral of cervical spine and thoracolumbar spine
      • three joint standing lower extremity films to assess alignment
  • Ultrasound
    • can be used to make diagnosis prenatally
Treatment
  • Nonoperative
    • observation and supportive treatment
      • indications
        • most patients
      • modalities
        • cauliflower ears frequently repsond to early treatment with compressive bandages
        • cervical kyphosis frequently resolves spontaneously
  • Operative
    • occipital-cervical fusion
      • indications
        • atlantoaxial instability with neurologic symptoms
          • risk of quadriplegia is a concern
    • posterior cervical fusion
      • indications
        • cervical kyphosis that does not resolve spontaneously
    • thoracolumbar fusion
      • indications
        • kyphoscoliosis of thoracolumbar spine
        • if progressive may require ASF / PSF
    • soft tissue surgical release
      • indications
        • early foot ankle deformity after initial period of casting
        • severe joint contractures (hip and knee)
    • osteotomies for correction
      • indications
        • progressive valgus deformity of lower extremities (with dislocated patellae)
        • resistant or recurrent clubfeet
        • distal femoral extension osteotomies for fixed knee flexion contractures
        • valgus intertrochanteric osteotomies +/- acetabuloplasty for early hip subluxation
    • total joint arthroplasty
      • indications
        • end stage osteoarthritis of hips
 

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Questions (4)

(OBQ12.8) A child with a defect in the DTDST gene would have which of the following classic phenotypes? Tested Concept

QID: 4368
1

Blue sclera and bowing deformities

7%

(326/4592)

2

Mental retardation and cardiac malformations

6%

(257/4592)

3

Cauliflower ears and hitchhiker's thumb

63%

(2912/4592)

4

Craniosynostosis and complex syndactyly

12%

(568/4592)

5

Rhizomelic dwarfism and frontal bossing

9%

(436/4592)

L 3 B

Select Answer to see Preferred Response

(OBQ09.49) What is the genetic cause of the dwarfism characterized by a hitchhikers thumb, cauliflower swelling of the ears, and severe clubfeet? Tested Concept

QID: 2862
1

FGFr-2

8%

(286/3560)

2

FGFr-3

11%

(386/3560)

3

Sulfate transport protein

69%

(2446/3560)

4

CBFA-1

8%

(271/3560)

5

Gs Alpha Protein

4%

(152/3560)

L 2 B

Select Answer to see Preferred Response

(OBQ05.29) Figure A is a photograph of a newborn's hand. Genetic testing reveals a mutation in the SLC26A2 gene on Chromosome 5q and both the parents were carriers. What condition does this child have? Tested Concept

QID: 66
FIGURES:
1

Achondroplasia

5%

(90/1734)

2

Osteogenesis imperfecta

1%

(10/1734)

3

Hypochondroplasia

7%

(119/1734)

4

Diastrophic dysplasia

82%

(1429/1734)

5

Ehlers-danlos syndrome

5%

(82/1734)

L 1 D

Select Answer to see Preferred Response

(OBQ04.104) A 3-year-old child with short-limbed dwarfism has the clinical features shown in Figures A & B. What is the pathoanatomy of this disease? Tested Concept

QID: 1209
FIGURES:
1

Sulfate transport protein gene mutation affecting cartilage matrix formation

74%

(774/1046)

2

Mutation in the gene CBFA-1 affecting osteocalcin formation

5%

(57/1046)

3

Defect in lysosomal-storage

4%

(43/1046)

4

Defect in lipid-storage

1%

(9/1046)

5

Mutation in gene FGFR-3 resulting in growth plate growth abnormality

15%

(158/1046)

L 2 B

Select Answer to see Preferred Response

Evidences (6)
VIDEOS (1)
Topic COMMENTS (8)
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