ATXN2 and amyotrophic lateral sclerosis: Alleles carrying 28–33 repeats are considered as intermediate expansions and may predispose to an elevated risk for ALS or the Parkinson plus syndrome PSP (82), ATXN2 expanded alleles present ≥32 triplet repeats with a large range of full penetrance above 35 repeats, which usually exhibit a pure CAG tract (83).