Biallelic expansion in RFC1 as a rare cause of Parkinson's disease.

An intronic expansion (AAGGG) exp in the RFC1 gene has recently been shown to cause recessively inherited cerebellar ataxia, neuropathy, and vestibular areflexia syndrome and, furthermore, a few patients with ataxia and parkinsonism have been reported. We investigated 569 Finnish patients with medicated parkinsonism for RFC1 and found biallelic (AAGGG) exp in three non-consanguineous patients with clinically confirmed Parkinson's disease without ataxia suggesting that RFC1-related disorders include Parkinson's disease as well.