Spinocerebellar ataxia 1 (SCA1)
General description
Spinocerebellar ataxia 1 (SCA1) is an autosomal dominant triplet repeat disease caused by extension of the CAG repeat of Ataxin 1 gene.
While childhood onset has been documented, the typical age of disease manifestation spans the third and fourth decades of life.
Initially, the disease produces slowly progressive cerebellar ataxia, pyramidal tract symptoms, oculomotor paralysis without nystagmus, peripheral neuropathy, and intellectual impairment.
References
- Kurokawa, Ryo, et al. "Clinical and neuroimaging review of triplet repeat diseases." Japanese Journal of Radiology 41.2 (2023): 115-130.
- Cocozza, Sirio, et al. "Conventional MRI findings in hereditary degenerative ataxias: a pictorial review." Neuroradiology 63.7 (2021): 983-999.
Atrophy
Almost all cases show atrophy of the cerebellum and brainstem, occasionally extending to the cerebral cortex, caudate nucleus, and putamen. The extent of atrophy is more severe than the degeneration of transverse pontine fibers.
Transverse pontine fiber lesion
Transverse pontine fiber degeneration may be present, but is milder than in Multiple system atrophy (MSA).