To stratify the analysis according to GRN mutation status, exons 1-13 (with exon 1 representing exon 0 in Gass et al.10) and adjacent intronic regions were sequenced as described13 in cases not previously evaluated. GRN sequencing was not possible due to limited sample quantity in a few cases (n=13 in GWA, n=15 in replication). Novel variants identified in this study not predicted to cause a frameshift or premature termination and previously described variants of uncertain significance were grouped with GRN mutation negative cases. The most common mutations identified are given in Supplementary Table 1.
