TPP1 and spinocerebellar ataxia 7: In line with this, missense alleles can be frequently identified in Spinocerebellar Ataxia 7, while approximately 60% of patients with CLN2 carry two common LOF mutations: the splice acceptor site mutation (c.509-1G > C) and the stop-gain mutation in exon 6 (c.622C > T, p.R208X), which may occur homozygously or heterozygously in trans (compound-heterozygously) with other disease alleles [1,8,41].