1 Porphyria Center Rotterdam, Center for Lysosomal and Metabolic Disorders, Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
2 Department of Pediatrics, Center for Lysosomal and Metabolic Disorders, Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands.
3 Porphyria Center Rotterdam, Center for Lysosomal and Metabolic Disorders, Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands. j.langendonk@erasmusmc.nl.