C9orf72 and mild neurocognitive disorder: This latter genetic change is characterized by an expansion of a hexanucleotide (GGGGCC) repeat region in the first intron or the promoter region of C9ORF72 gene, occurring in patients with either FTLD or MND, or a combination of both [6–8], and can number in excess of as many as 1500 repeats [9].