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Paediatrics FCRS > Proportionate Dwarfism > Flashcards

Proportionate Dwarfism Flashcards

Cleidocranial syndrome Mucopolysaccharidosis: morquio Syndrome San Filippo Syndrome Hurler's syndrome Hunter syndrome

1
Q

Name the conditions that cause proportionate dwarfism?

A
  • Cleidocranial dysostosis
  • Mucopolysaccraridoises
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2
Q

What is cleidocranial dysplasia ( Dysostosis)?

A
  • A skeletal dysplasia affecting bones formes by INTRAMEMBRANOUS OSSIFICATION
    • ​e.g. facial bones, clavicle, cranium
  • Approx 1 in 1,000,000 affected
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3
Q

What is the pathophysiology of cleidocranial dysplasia?

A
  • Caused by a defect in intramembranous ossification
  • leads to failure of formation of MIDLINE structures
  • Characteristic feature is hypoplastic/ absent clavicles
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4
Q

What is the genetics of cleidocranial dysplasia?

A
  • Autosomal dominant
  • RUNX2 / CBFA1 mutation
    • transcription factor which regulates osteoblastic differentiation
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5
Q

What are the orthopaedic manifestation of cleidocranial dysplasia?

A
  • Proportionate dwarfism
  • Clavicle dysplasia/aplasia
  • wormian bones
  • frontal bossing
  • delayed fontanelle closing
    • due to dealy closure of skull sutures
  • Coxa vara
  • shortened middle phalanges 3-5 fingers
  • delayed ossification of pubis
  • dental abnormalities
    • delayed eruption of permanent teeth
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6
Q

What are the signs and symptoms of cleidocranial dysplasia?

A
  • Usually asymptomatic

Signs

  • Hypermobility of shoulders- see pic
  • frontal bossing
  • hand deformities
    • examine middle finger phlanges for shortening
  • delayed formation of permanent teeth
  • abnormal range of motion of hips
    • severe coxa vara maybe present
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7
Q

What imaging is useful in cleidocranial dysplasia?

A
  • Ap chest
    • To identify clavicle dysmorphism
  • Lateral skull
    • look for delayed closure of sutures
  • Ap pelvis
    • look for coxa vara
    • look for failure
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8
Q

What is the tx for cleidocranial dysplasia?

A

Non operatively

  • Observation
    • Clavicle hypoplasia
    • most manifestations assoc with disease don’t need intervention

Surgery

  • Intertrochanteric osteotomy
    • for coxa vara w a neck shaft angle <100 degrees
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9
Q

Describe the what is mucopolysaccharidoses and the forms of it ?

A
  • A group of 13 metabolic syndromes caused by the absence or malfunctioning of Lysosomal enzymes which break down Glycoaminoglycans
  • Main forms
    • “Maltesers Sadly Hit Home”
    • Morquio
    • San Filippo
    • Hurler’s
    • Hunters
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10
Q

What is the pathophysiology of mucopolysaccharidoses

A
  • Lysosomal storage disorder due to incomplete glycosaminoglycan breakdown products ( mucopolysaccharides) accumulating and causing dysfunction in various organs
  • Glycosaminoglycans are long chain sugar carbohydrates chains that build bone, cartilage , tendons, corneas, skin and connective tissue
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11
Q

What are the associated orthopaedic manifestations of mucopolysaccharidoses?

A
  • Proportionate dwarfism
  • Increased rate of Carpal tunnel syndrome
  • C1-2 Instability
  • Delayed Hip Dysplasia
  • Abnormal Epiphysis
  • Bullet shaped Phalanges
  • shortened ulna with Madelung’s deformity
  • Genu Valgum
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12
Q

Name the non orthopaedic conditions of mucopolysaccharidoses?

A
  • Complex sugars in urine
  • Visceromegaly
  • Corneal clouding
  • cardiac disease
  • Deafness
  • mental retardation - except Morquio syndrome
  • enlarged skull
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13
Q

What is the prognosis of mucopolysaccharidoses?

A
  • Bone marrow transplant improves life expectancy but DOESN’T alter orthopaedic manifestations
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14
Q

what are the lab test for mucopolysaccharidoses?

A
  • urine
    • Toluidine blue spot test- to analyze the excess mucopolysaccharides
  • Skin fibroblast culture to test enzyme activity
  • Chorionic villus sampling
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15
Q

What is Morquio syndrome?

A
  • Most common mucopolysaccharidosis characterised by
  • accumulation of Keratan Sulphate
    • ​it interferes with Cartilage of growth plate
    • present at 18-24 months
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16
Q

What is the pathophysiology of Morquio syndrome?

A
  • Type A = Galactosamine-6-sulphate-sulphatase deficiency
  • Type B= Beta-galactosidase deficiency
17
Q

What is the genetics of `morquio syndrome?

A
  • Autosomal recessive
18
Q

What is the prognosis of morquio syndrome?

A
  • Type A- More Severe
  • type A and B survive to adulthood
19
Q

What do pts with morquio syndrome present with?

A
  • Proportinate dwarfism
  • Normal IQ
  • waddling gait
  • Genu Valgum
  • Thoracic Kyphosis
  • corneal clouding
20
Q

What are seen on radiographs in pts with morquio syndrome?

A
  • Thickened skull
  • wide ribs
  • Vertebral beaking
  • coxa vara with unossifiec femoral head
  • bullet shaped metacarpals
  • odontoid hypoplasia -> atlantoaxial instability
  • thoracic kyphosis with platyspondia
21
Q

What is the tx of morquio syndrome?

A
  • Decompression and cervical fusion
    • for myelopathy with C1-2 instability or >5mm instability in asymptomatic p
  • realignment osteotomies
    • restores plumb alignment in limb
    • malaligment commonly reoccurs
  • Guided growth
    • alternative to osteotomies but lack of evidence
22
Q

What is San Filippo syndrome?

A
  • A form of mucopolysacharidoses characterised by accumulation of Heparan Sulphate
  • Autosomal Recessive
23
Q

What is the pathophysiology of San Filippo syndrome?

A
  • Multiple enzyme deficiencies
24
Q

What is the prognosis of San Filippo syndrome?

A
  • death in second decade of life
25
Q

What is the presentation of a child with San Filippo syndrome?

A
  • Mental retardation
  • Proportinate Dwarfism
  • Clear Cornea
26
Q

What lab studies are useful in San Filippo syndrome?

A
  • Urine
    • Heparan Sulphate in urine
27
Q

What is the tx fo San Filippo syndrome?

A
  • Bone marrow transplant
    • has increased lifespan
28
Q

What is this?

A
  • Hurler’s syndrome
  • the most Severe Mucopolysaccharidosis
  • charcterised by accumulation of Dermatan Sulphate
  • Autosomal Recessive
29
Q

What is the pathophysiology of Hurler’s syndrome?

A
  • Caused by alpha-L iduronidase deficiency
30
Q

What is the prognosis of Hurler’s syndrome?

A
  • Death in first Decade of life
31
Q

What are the signs of Hurler’s syndrome?

A
  • Proportionate dwarfism
  • Progressive mental retardation
  • cloudy cornea
  • Genu Valgum
  • C1-2 Instability (25%)
  • Carpal tunnel syndrome and finger triggering
32
Q

Which lab test is useful in hurley’s syndrome?

A
  • urine
  • dermatan Sulphate in the urine
33
Q

What is the tx for Hurler’s syndrome?

A
  • A bone marrow transplant
    • if preformed in first year of life extends life span
    • doesn’t change orthopaedic phenotypic changes
34
Q

What is Hunter’s syndrome?

A
  • A mucopolysaccharidosis characterised by accumulation of Dermatan/Heparan sulphate
  • X linked Recessive ( unlike others autosomal R)
35
Q

What is the pathophysiology of Hunter syndrome?

A
  • Sulpho-iduronate-sulphatatse deficiency
36
Q

What is the prognosis of hunter syndrome?

A
  • Death by 2nd decade of life
37
Q

what is the presentation of a child with Hunter syndrome?

A
  • Mental retardation
  • Proportinate Dwarfism
  • Clear cornea
38
Q

What lab studies are useful with Hunter syndrome?

A
  • Urine
    • Dermatan/Heparan Sulphate iin Uribe
39
Q

Can you give an overview of the 4 mucopolysacccharidosis conditions

A

Paediatrics FCRS (27 decks)

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