Fourth, we have sequenced every known gene and predicted transcripts in the candidate region as defined by the minimal interfamily haplotype shared by the Dutch, Scandinavian and North American ALS-FTD families (figure 1) and the gene encoding IFT74 was the only gene that contained variants not identified in the general population and fifth, these mutations are not present in 900 to 1,000 North American control chromosomes. Here, IFT74 is linked to frontotemporal dementia.