RFC1 and Parkinson disease: Recent studies have suggested that biallelic RFC1-AAGGG REs are a rare cause PD, finding three biallelic carriers in a Finnish cohort of 569 individuals with PD (0.53%)15, an additional three cases in a follow up study in a Finnish cohort of 273 early-onset PD cases (1.1%) and four biallelic PD cases in the Parkinson’s Progression Markers Initiative (PPMI) cohort looking at 903 (0.44%) non-Finnish Europeans with PD, with none in controls16.