C9orf72 and amyotrophic lateral sclerosis: Whereas no C9orf72 expansions were found in the Charmorro population [41], 3 (20 %) ALS cases carried an expansion in the Kii Peninsula, a frequency significantly higher than across the rest of Japan, suggesting C9orf72 expansions do contribute to the prevalence of ALS in this high incidence geographical focus [42].