To validate the specificity of FMR1 DNA (hydroxy)methylation perturbations, additional control genomic regions were investigated from the array data and validated by (h)MeDIP-PCR and did not display differential 5mC/5hmC distribution or enrichment in healthy controls and FXS samples (Fig. 1b, Additional file 2: Figure S1C and Additional file 3: Figure S2C). Here, FMR1 is linked to fragile X syndrome.