HDAC1 and Buschke-Ollendorff syndrome: To validate the expression data, as the histone deacetylases class I was the most over-represented epigenetic enzymes identified in MSC of BOS patients and, in particular, among these, HDAC1 was the most highly expressed, we analysed its expression in lung tissues from patients with BOS (n = 4) and stable LTRs (n = 4).