GAA-FGF14 Disease: Defining Its Frequency, Molecular Basis, and 4-aminopyridine Response in a Large Cohort of Patients with Downbeat Nystagmus (P6-3.013)

Reassess the clinical and molecular spectrum of GAA-FGF14 disease by studying the frequency of FGF14 (GAA)≥250 and (GAA)200–249 expansions in patients with idiopathic downbeat nystagmus (DBN) syndromes and their phenotypic spectrum. Provide real-world and placebo-controlled data on 4-aminopyridine treatment response.