A novel frameshift mutation in FGF14 causes an autosomal dominant episodic ataxia

Episodic ataxias (EAs) are a heterogeneous group of neurological disorders characterized by recurrent attacks of ataxia. Mutations in KCNA1 and CACNA1A account for the majority of EA cases worldwide. We recruited a two-generation family affected with EA of unknown subtype and performed whole-exome sequencing on two affected members. This revealed a novel heterozygous mutation c.211_212insA (p.I71NfsX27) leading to a premature stop codon in FGF14. Mutations in FGF14 are known to cause spinocerebellar ataxia type 27 (SCA27). Sanger sequencing confirmed segregation within the family. Our findings expand the phenotypic spectrum of SCA27 by underlining the possible episodic nature of this ataxia.