Statistical tests for association were performed using plink. Single marker analyses for the genome-wide data were done using the Cochran-Armitage trend test. The genomic inflation factors were 1.05 for the complete case set and 1.03 for the GRN mutation carriers, indicating only minor background stratification. The Breslow-Day test within plink was used to test for heterogeneity of odds ratio for the disease/SNP association between GRN mutation carriers and non-carriers. Conditional SNP regression analyses were completed in plink, the allele dosages of the conditioning SNP were included as covariates in the logistic regression models. To determine if the association at the TMEM106B locus was dependent on family history we included family history status as a covariate in a logistic regression model using plink. Haplotypes were reconstructed and population frequencies estimated using the EM algorithm implemented in the program fastPHASE28. For the age of onset and disease duration analyses we performed an analysis of variance (ANOVA) with the general linear models procedure in R (www.r-project.org). Independent variables for each ANOVA were the log transformed age of onset or disease duration in years
