The distinction in mean number of methylated genes in the PC group (8.41 (95% CI 7.62–9.20)) versus the aggregate control group (4.74 (95% CI 4.40-5.08)) was highly significant (p < 0.001). Additionally, a diagnostic prediction model (age > 65, BMP3, RASSF1A, BNC1, MESTv2, TFPI2, APC, SFRP1 and SFRP2) had an area under the curve of 0.86 (sensitivity 76%, specificity 83%). The gene discussed is APC; the disease is pachyonychia congenita.