FMR1 and fragile X syndrome: To determine whether FXS-associated DNA methylation changes were present in these individuals, we analyzed each locus using a linear mixed-effects regression model that adjusted for age (see Methods) and identified 17 differentially methylated probes, 15 of which are annotated to the FMR1 promoter or gene body: 14 FXS-methylated loci and 1 FXS-demethylated locus (Bonferroni <0.05; Figure 1 A, B; Additional file 2: Table S1 and Additional file 3: Table S2).