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spinocerebellar-ataxia

Disease Info

Combined prevalence	Approximately 1–5 per 100,000 worldwide, though rates vary significantly by region and ethnicity
SCA3 (Machado-Joseph disease)	The most common SCA globally, particularly prevalent in Portugal, Brazil, Japan, and China. Accounts for approximately 21–36% of all SCA cases
SCA2	Second most common worldwide; particularly prevalent in Cuba (40 per 100,000 in Holguín Province, the world's highest known concentration)
SCA1	Third most common; relatively uniform distribution
SCA6	More common in Japan and older-onset populations; accounts for 13–15% of dominant ataxias in Japan
SCA7	Rare in most populations but relatively common in parts of South Africa and Scandinavia
Age of onset	Most subtypes present between ages 20–50, though childhood and late-onset forms occur. Earlier onset generally correlates with larger repeat expansion sizes (genetic anticipation)
SCA5	Missense mutations in SPTBN2 (β-III spectrin), disrupting Purkinje cell dendritic architecture
SCA14	Mutations in PRKCG (protein kinase C γ), causing aberrant signaling
SCA27	Mutations in FGF14, disrupting voltage-gated sodium channel function
SCA28	Mutations in AFG3L2, causing mitochondrial protease dysfunction
High metabolic demand	Purkinje cells are among the largest and most metabolically active neurons in the brain
Databases	OMIM Orphanet ClinicalTrials PubMed

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