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Strabismus & Ocular Motility > Congenital Cranial Dysinnervation Disorders (CCDD) > Flashcards

Congenital Cranial Dysinnervation Disorders (CCDD) Flashcards

1
Q

What does dysinnervation mean?

A

Lacking normal innervation, sometimes including aberrant innervation

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2
Q

What does CCDD stand for?

A

Congenital Cranial Dysinnervation Syndrome

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2
Q

What are examples of CCDDs?

A
  • Congenital fibrosis of EOMs
  • Duane’s
  • Brown’s (may be due to nodule on SO complex abnormality)
  • Congenital Ptosis
  • Strabismus Fixus (may be secondary to myopia, trauma and EOM injury)
  • Double elevator palsy (may be acquired)
  • Congenital Ophthalmoplegia
  • Congenital SO palsy
  • Horizontal gaze palsy with progressive scoliosis
  • Marcus Gunn Syndrome
  • Moebius syndrome
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3
Q

How do we define CCDD?

A

‘Subgroup of strabismus classified by being congenital, non-progressive ophthalmoplegia with restriction of globe movement in one or more fields of gaze’ (Gutowski et al 2003)

& characterised by hypoplasia of cranial nerve

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4
Q

What is primary dysinnervation?

A
  • Absence of normal innervation
  • Neurons do not develop/develop abnormally
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5
Q

What is secondary dysinnervation?

A
  • Aberrant developmental innervation by branches of another nerve
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6
Q

What are crocodile tears an example of? Primary or secondary dysinnervation?

A

Crocodile tears – aberrant innervation between facial nerve (VII) salivary fibres innervating the lacrimal gland. Can be congenial and is commonly associated with Duane’s and Möbius

  • An autopsy of Duane’s have shown an anatomical absence of the abducens nerve
  • An autopsy of CFEOM have shown a bilateral absence of the superior division of CN3
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7
Q

What have CCDD genetic studies discovered?

A

Studies in mice and zebrafish have shown a change in the PHOX2A gene has resulted in a loss of oculomotor and trochlear nuclei and nerves and other changes

70% of human genes are found in Zebra fish

Zebrafish have 2 eyes, brain, spinal cord, muscle, bone, cartilage and teeth. Many of the genes and critical pathways that are required to grow these features are highly conserved between humans and zebrafish

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8
Q

What does CFEOM stand for?

A

Congenital fibrosis of EOMs

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9
Q

What do we observe in CFEOM?

A
  • Chin-up AHP
  • Bilateral ptosis
  • Frontalis overaction
  • Lack of lid crease
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10
Q

What causes CFEOM?

A

CFEOM - Congenital Fibrosis of EOMs
(Baumgarten, 1840)

  • Initially considered to be due to primary fibrosis of EOM
  • Electromyography and genetic studies have proven these conditions are caused by developmental abnormalities of cranial nerve/nuclei, causing abnormal or absent innervation with primary or secondary dysinnervation

i.e. primary neuropathy with secondary myopathy

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11
Q

What are some clinical characteristics of CFEOM?

A
  • Non-progressive
  • Dysinnervation leading to fibrosis of muscles innervated by CNIII, CNIV and CNVI
  • Restricted ophthalmoplegia & ptosis (fibrosis of EOMs, fibrosis of Tenon’s capsule, adhesions between muscles/tenon’s capsule’globe, inelasticity of conjunctiva)
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12
Q

What is the inheritance of CFEOM?

A
  • CFEOM1 & CFEOM3 are autosomal dominant
  • CFEOM2 is autosomal recessive
  • Sporadic (less common)
  • Affects males and females equally
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13
Q

What is the inheritance of CFEOM1 and CFEOM3?

A

CFEOM1 & CFEOM3 are autosomal dominant

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14
Q

What is the inheritance of CFEOM2?

A

CFEOM2 is autosomal recessive

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15
Q

What is the most common CFEOM type?

A

CFEOM1 (dominant inheritance)

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16
Q

What are features of CFEOM1?

A
  • Bilateral ptosis
  • Severe restriction on upgaze (neither eye can reach midline). Downgaze and horizontal movement variable restricted. Generally symmetrical
  • Large bilateral hypotropia with exotropia or esotropia
  • AHP – chin up
  • Misdirected eye movements common, including bilateral convergence on attempted up gaze
    Not associated with other neurological abnormalities
  • KIF21A gene
17
Q

What type of inheritance is the CFEOM2 subtype?

A

Recessive Inheritance (PHOX2A)

18
Q

What are features of CFEOM2?

A
  • Bilateral ptosis and absent adduction, upgaze, and downgaze, appearance like bilateral 3rd nerve palsies. Abduction present but can be incomplete.
  • Pupils may be small and nonreactive to light
  • Neuroimaging shows 3rd nerve are absent bilaterally
  • May have subnormal VA consistent with retinal dysfunction
  • No additional neurological abnormalities
19
Q

What type of inheritance is CFEOM3?

A

Dominant inheritance (TUBB£)

20
Q

What is TUBB3?

A

A CFEOM3 Dominant Inheritance subtype

21
Q

What are features of CFEOM3?

A

Similar to CFEOM1 except can be more variable presentation, and may have the ability to elevate eyes above midline

Can have associated facial palsy, peripheral neuropathy, vocal cord paralysis, wrist and finger contractures, brain malformations, intellectual, social and behavioural impairments.

22
Q

What is Tukel Syndrome?

A

A type of CFEOM (Congenital Fibrosis of Extraocular Muscles)

Gene location 21q22 - TUKLS

Recessive Inheritance

23
Q

What are the features of Tukel Syndrome?

A
  • Same features as CFEOM3 but mainly unilateral
  • Bilateral postaxial oligodactyly or oligosyndactyly (missing bones) of hands
  • Absent or fused carpel bones
24
Q

What Orthoptic investigations are important in CFEOM?

A
  • AHP documentation
  • VA
  • Pupils
  • CT
  • OM
  • Observe Bell’s Phenomenon *
  • BSV tests with AHP
25
Q

What Ophthalmology investigations are important in CFEOM?

A
  • Fundus and media check
  • Refraction
    High levels of myopia and astigmatism not uncommon
  • Reduced VA ERG/OCT
    Abnormal rod and cone function found in 10 px with CFEOM2 (Kahn et al 2015)
  • Genetic testing
26
Q

What must be consider in CFEOM when testing?

A

Neither eye can move to take up central fixation

  • VA assessment
  • CT recording
  • Measurement of deviation
27
Q

What management must we consider in CFEOM?

A
  • Amblyopia
    Strabismic or stim deprivation
  • Strabismus surgery
    To alleviate AHP or for cosmesis
    (FDT +ve for fibrosis, MRI indicates level of fibrosis, reduced thickness of EOM and abnormal nerves, ideally to recess fibroses muscles, think TED)
  • Ptosis surgery
    Brow suspension (frontalis overaction). Beware corneal exposure due to absent bells.
28
Q

What surgical management do we do in CFEOM?

A

Stepwise surgical approach
- FDT +ve for tight LIR muscle
- Adhesions and fibrosis bands released
- Large LIR recession (12mm) on adjustables
- Adjustment performed within 1 week

29
Q

What’s is HGPPS?
Hint: subtype of CCDD (Congenital cranial dysinnervation disorders)

A

Horizontal gaze palsy with progressive scoliosis

30
Q

What are features of HGPPS?

A
  • Rare recessive CCDD
  • 2 reported types
  • Only a several dozen known cases (consanguineous families)
31
Q

What gene is affected in HHGPS Type 1?

A

ROBO3 gene - 11q24.2

32
Q

What are features of HHGPS Type 1?

A
  • Bilateral horizontal gaze palsies with affected smooth pursuits, saccades, and VOR
  • Preserved convergence
  • External ophthalmoplegia (onset at birth)
  • Progressive Scoliosis (onset from as young as 2yrs)
  • Pontine and cerebellar hypoplasia
  • Extensive hindbrain and spinal cord miswiring
33
Q

In HGPPS Type 1 how is convergence preserved but horizontal gaze is affected bilaterally?

A

Convergence and horizontal gaze are controlled in separate areas of the brain:

  • The PPRF nucleus is the key structure in conjugate horizontal gaze and horizontal saccades. It receives information from the higher cortical centres such as the frontal eye fields, occipital and parietal lobes, and the superior colliculus
  • The convergence pathway is separate and includes the fibres from the medial rectus subnucleus of the CN III
34
Q

What area of the brain is horizontal gaze controlled in?

A

The PPRF nucleus is the key structure in conjugate horizontal gaze and horizontal saccades. It receives information from the higher cortical centres such as the frontal eye fields, occipital and parietal lobes, and the superior colliculus

35
Q

What area of the brain is convergence controlled in?

A

The convergence pathway is separate to that of horizontal gaze and includes the fibres from the medial rectus subnucleus of the CN III

36
Q

What gene is affected in HHGPS Type 2?

A

DCC gene 18q21.2

37
Q

What are features of HHGPS Type 2?

A
  • Bilateral horizontal gaze palsy
  • Progressive Scoliosis
  • Muscular hypotonia
  • Delayed psychomotor development
  • Intellectual disability
  • Hypoplastic pons and midbrain
  • Decreased axonal integrity and myelination
38
Q

What type of disorder is Congenital Ptosis?

A

CCDD

39
Q

What gene is affected in Congenital Ptosis?

A

PTOS1 Gene

40
Q

What are the features of Congenital Ptosis?

A
  • Dominant inheritance pattern
  • Isolated congenital ptosis
  • Size variable
  • Unilateral or bilateral
  • Frequently require surgery to elevate eyelids (see ptosis lecture)
  • An x-linked type has been described but no gene found

Strabismus & Ocular Motility (23 decks)

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