Three genes are differentially methylated in lymphocytes of patients with PBC and systemic sclerosis (32) and may thus be representative of general autoimmunity or fibrosis development; these genes include MTM1 hypermethylated in PBC and in systemic sclerosis while SSR4 and IGH3G are hypomethylated in both diseases. The gene discussed is MTM1; the disease is systemic sclerosis.