Moreover, our study confirms previous findings in patients with EPP and in the erythroleukemic cell line K562 showing that ALAS2 and FECH mRNA expression positively correlates both in EPP and CTRL (Figures 3A,B) (Barman-Aksözen et al., 2019). This evidence concerns the gene CTRL and autosomal erythropoietic protoporphyria.