To determine whether the results obtained in vitro reflected what occurs in the ERS gingiva we analysed the distribution of p-Smad3 and the TGFβ targets Netrin1 and COL6A in the gingival connective tissue of unaffected subjects and ERS patients (Figure 5 and Supplementary Figure 2). The gene discussed is TGFB1; the disease is amelogenesis imperfecta type 1G.