Thread by @theneurolander

Hereditary Ataxias!!!
Spinocerebellar ataxias (SCA)

“SCA1 …. the unstable CAG trinucleotide repeat expansion”

American geneticist Harry T. Orr

#MedTwitter #neurotwitter #EndNeurophobia #tweetorials

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SCA definition

“complex group of heterogeneous degenerative diseases of the cerebellum and its connections”

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Worldwide distribution of SCA subtypes

21% SCA3, Brazil & Portugal
15% SCA2, India & Singapore
15% SCA6, Japan & Germany
6% SCA1, South Africa
5% SCA7, South Africa
3% SCA8, worldwide

<1% rare
SCA 10, SCA 12, SCA 14, SCA17

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SCA1

“ophthalmoplegia + spasticity + extrapyramidal signs”

- ATXN1, AD
- anticipation w/ paternal transmission
- 1st identified
- best understood at molecular level

doi.org/10.1007/978-1-… via: Movement Disorders: A Video Atlas

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SCA2

“early slow oculomotor saccades, ophthalmoplegia, fasciculations, extrapyramidal signs”

- infantile, onset
- associated w/ dementia & muscle cramping
- ATXN2, AD
- anticipation w/ paternal transmission
- Cuban population

doi.org/10.1007/978-1-… via: Mov Disord

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SCA3

“ophthalmoplegia, vestibular involv, fasciculations, neuropathy, spasticity, extrapyramidal signs”

-severe vertigo & muscle cramping
-Machado-Joseph disease
-most freq SCA
-Portuguese pop
-anticipation w/ paternal transmission

doi.org/10.1007/978-1-… via: Mov Disord

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SCA6

“downbeat nystagmus & vestibular involvement”

- after age 50y, onset
- episodic ataxia
- severe vertigo
- CACNA1A
- anticipation is not seen

doi.org/10.1007/978-1-… via: Mov Disord

7/

SCA7

“early slowed oculomotor saccades, spasticity”

- infantile onset
- associated w/ seizure & retinopathy
- macular dystrophy

doi.org/10.1007/978-1-… via: Mov Disord

8/

SCA8

“saccadic dysmetria and gaze-evoked nystagmus”

- mild disease
- ATXN 8, ATXN8 OS
- AD
- maternal anticipation

collections.lib.utah.edu/ark:/87278/s6d… via: UTAH

9/

SCA10

- associated w/ seizures
- ATXN 10
- Mexican population
- paternal anticipation
- SCA2&SCA10

doi.org/10.1001/archne… via: JAMA

10/

SCA12

“action tremor, progressive ataxia, subtle parkinsonism”

- PPP2R2B

doi.org/10.1002%2Fmdc3… via: Mov Disord

11/

SCA14

- PRKCG
- AD

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SCA17

“extrapyramidal signs”

- dementia
- TBP
- AD

doi.org/10.1007/978-1-… via: Mov Disord

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Algorithm - age

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Algorithm – clinical manifestation

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Algorithm – oculomotor sign

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Ophthalmologic manifestations of SCA

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