2 Clinical Epidemiology Unit, IDI-IRCCS, Rome, Italy.
3 Dermatology Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
4 Multifactorial and Complex Disease Research Area, Bambino Gesù Children's Hospital IRCCS, Rome, Italy.
5 Department of Dermatology, Necker-Enfants Malades Hospital, Centre de Référence National pour les Maladies Génétiques à Expression Cutanée (MAGEC), APHP, Paris, France.