1 Department of Dermatology, Academic Medical Centre, Netherlands Institute for Pigment Disorders, University of Amsterdam, Amsterdam, The Netherlands.
2 Department of Dermatology, Academic Medical Centre, Netherlands Institute for Pigment Disorders, University of Amsterdam, Amsterdam, The Netherlands; Department of Dermatology, Medical Centre Haaglanden, The Hague, The Netherlands.
3 Department of Dermatology, Academic Medical Centre, Netherlands Institute for Pigment Disorders, University of Amsterdam, Amsterdam, The Netherlands; Department of Dermatology, VU Medical Centre, Amsterdam, The Netherlands.