FGF14 associated with idiopathic downbeat nystagmus at 200–249 repeats

[hdashnow]

Idiopathic downbeat nystagmus associated with smaller FGF14 expansions (below the current pathogenic threshold for SCA)
https://www.thelancet.com/journals/ebiom/article/PIIS2352-3964(24)00111-7/fulltext
Genetic testing for FGF14 GAA repeat expansions should now become part of the routine diagnostic work-up of patients with idiopathic downbeat nystagmus, especially in the presence of additional cerebellar signs, as they account for a significant proportion of cases. This study provides evidence for the potential pathogenicity of alleles of 200–249 repeats and adds several lines of evidence for the treatment efficacy of 4-aminopyridine in GAA-FGF14 disease. It further paves the way toward clinical trials of 4-aminopyridine in GAA-FGF14 disease.