Clinical, genetic, and ultrasonographic features of Periumbilical Perforating Pseudoxanthoma Elasticum. Issue 4 (27th February 2021) - Maronese, Carlo Alberto; Spigariolo, Cristina Beatrice; Boggio, Francesca Laura; Moltrasio, Chiara; Brena, Michela; Zelin, Enrico; Genovese, Giovanni; Marzano, Angelo Valerio; Nazzaro, Gianluca