Ataxia, spastic, Charlevoix-Saguenay type
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(ARSACS acronym Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay).
Cause of at least 5 % of the early-onset spinocerebellar ataxia cases. It could be the second cause of congenital ataxia after Friedreich's disease. Most common in the region of Charlevoix-Saguenay in Canada (incidence estimated at 1/1,932).
Autosomal recessive transmission of a mutation of the SACS gene on 13q 11. This gene codes for a large protein called sacsin, that could mediate the three-dimensional conformation of other proteins.
Neurodegenerative disease that combines to varying degrees:
- cerebellar ataxia: early-onset in the Quebec form (around 12-18 months), later-onset in other countries; difficulties for walking, dysarthria, nystagmus
- progressive spasticity (less severe in Japanese patients)
- pyramidal syndrome
- peripheral neuropathy: onset is later and results in a distal amyotrophy, abolition of some reflexes, deep sensitivity disorders. EMG: decrease in motor and sensory conduction speeds
- MRI: early-onset atrophy of the upper part of the cerebellar vermis and the cerebellar hemispheres (sometimes also of the parietal cortex), and finally the cervical spine; often arachnoid cyst in the posterior fossa
- ophthalmoscopy (in Quebec form): hypermyelination of the optic nerve fibers that spread out of the optical disc and accompany the retinal vessels
Also:
- mitral valve prolapse
- pes cavus
- bladder dysfunction: unstable bladder
- epilepsy: 7 %
Treatment: physiotherapy, occupational therapy, psychological support.
Anesthetic implications:
preoperative cardiac ultrasound (mitral valve prolapse?); difficulties to monitor curarization
References :
- Martin M-H, Bouchard J-P, Sylvai M, St Onge O, Truchon S.
Autosomal recessive spastic ataxia of Charlevoix-Saguenay: a report of MR imaging in 5 patients.
AJNR 2007; 28: 1606-8.
- Synofzik M, Soehn AS, Gburek-Augustat J et al.
Autosomal recessive spastic ataxia of Charlevoix Saguenay (ARSACS) : expanding the genetic, clinical and imaging spectrum.
Orphanet J Rare Diseases 2013; 8:41
Updated: November 2019