C9orf72 and amyotrophic lateral sclerosis: Since V3 and V2 encode the same protein, and the part of V1 and V3 in the total fraction of C9ORF72 mRNAs is minor, this will nevertheless not affect the general result that there is an overall decrease of ∼50% of C9ORF72 transcripts and that C9ORF72 protein levels might be correspondingly reduced in C9-FTD/ALS patients.