C9orf72 and amyotrophic lateral sclerosis: Although the pathogenesis of ALS is still unknown, extensive studies have revealed important genetic risk factors in the past decade.C9orf72 (#MIM 105550),SOD1 (#MIM105400),TARDBP (#MIM612069, #MIM612069), andFUS (#MIM608030) are the most frequently mutated genes that have been shown in ALS,2,3 with the hexanucleotide repeat expansion inC9orf72 being the most significant and accounting for 30–50% of familial and 7% of sporadic ALS cases in the European population.2,3 However, the genetic basis of ALS has not been investigated in the Transcaucasian region.