UROS and Congenital erythropoietic porphyria: Congenital erythropoietic porphyria (CEP, OMIM #263700), also known as Gunther’s disease, is a rare autosomal recessive disorder caused by mutations in the UROS gene, leading to reduced activity of uroporphyrinogen-III-synthase (UROS) (Mirmiran et al., 2021).