As previous studies have shown the pivotal role of genetically homogeneous populations, such as the Ashkenazi Jews (AJ), in understanding the genetic background of neurodegenerative diseases [24,25,26,27], we hereby determined C9orf72 repeats’ size in PD patients of Ashkenazi origin and examined their potential association with PD. Here, C9orf72 is linked to neurodegenerative disease.