We would like to thank Chiara Di Giorgio (Fondazione IRCCS Casa Sollievo della Sofferenza, Italy) for reviewing this manuscript for English language. CSS Porphiria Study Group* Guida Claudio Carmine (1), Pellegrino Angela Maria (1), Nardella Maria (1), Perez Ys Aurora Del Mar(1), Prencipe Michele Antonio (1), Napolitano Francesco (1), Ferrara Gaetano (1), Crisetti Annalisa (1), Carosi Illuminato (2) Aucella Francesco (1), Aucella Filippo (ORCID ID 0000-0003-1027-7049) (1). (1) Department of Medical Sciences, Division of Nephrology and Dialysis; (2) Pathology Unit Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Viale Cappuccini 71013 San Giovanni Rotondo (Foggia), Italy.