C9orf72 and amyotrophic lateral sclerosis: In our first C9orf72 study in the Flanders-Belgian cohort [Gijselinck et al., 2012], we showed that the majority of the pathological G4C2 expansions were located on the same risk haplotype tagged by the rare T-allele of SNP rs2814707, and strongly associated with FTLD and ALS.