Fig. 1

a Volcano plot of methylation difference (estimate) between ATR-X and controls versus statistical significance (log p value) of individual probes. In red are highlighted probes with estimate value higher than 0.15. Positive estimate value = hypermethylation; negative estimate value = hypomethylation. b Histogram of all samples showing methylation value (X-axis) versus frequency of methylation levels across the genome (Y-axis) in ATR-X patients (red) and controls (blue). Patients with ATR-X showed a higher frequency of methylation at low methylation value regions (0.1–0.2 methylation value). Low methylation value regions are characteristic of promoter CpG islands. c Hierarchical clustering of probes differentially methylated (p < 0.01) between ATR-X and controls demonstrating marked asymmetry of the two groups. Cases are represented in the columns and probes in the rows