KLK15 and fragile X syndrome: Though the 15 FMR1-associated loci exhibit a unique FXS-associated DNA methylation profile of distinct methylation levels with little overlap for FXS samples versus controls (Figure 1B), the two autosomal differentially methylated loci (KLK15 and MICA) were not so distinct; they were also hypomethylated rather than hypermethylated and were not flanked by other significantly differentially methylated loci, as one sees at FMR1 (Additional file 5: Figure S2).