First Report of Co-Occurring FGF14 (SCA27B) and RFC1 (CANVAS) Repeat Expansions in Two of Three Siblings with Late-Onset Cerebellar Ataxia.

ABSTRACT: Cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS) and spinocerebellar ataxia type 27B (SCA27B) are two increasingly recognized types of late-onset ataxia caused by biallelic RFC1 AAGGG and heterozygous FGF14 GAA repeat expansions, respectively. We describe three siblings of Greek-Cypriot origin with late-onset cerebellar ataxia. Two brothers carried biallelic pathogenic RFC1 AAGGG expansions and heterozygous FGF14 GAA expansions (338-350 repeats), establishing a dual diagnosis of CANVAS and SCA27B. Both presented with progressive gait ataxia, vestibular dysfunction, and sensory neuronopathy; one also reported episodic symptoms typical of SCA27B. Their sister, heterozygous for RFC1 and carrying a pathogenic FGF14 expansion (325 repeats), showed a pure SCA27B pheno

SUBMITTER: Tsokkos T 

PROVIDER: S-EPMC12540548 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature