A deficiency is associated with Gunther's disease, also known as congenital erythropoietic porphyria (CEP). This is an autosomal recessive inborn error of metabolism that results from the markedly deficient activity of uroporphyrinogen III synthase .
^To-Figueras J, Badenas C, Mascaro JM, Madrigal I, Merino A, Bastida P, Lecha M, Herrero C (2007). "Study of the genotype-phenotype relationship in four cases of congenital erythropoietic porphyria". Blood Cells Mol. Dis.38 (3): 242–6. doi:10.1016/j.bcmd.2006.12.001. PMID17270473.