Feline Congenital Erythropoietic Porphyria: Two Homozygous UROS Missense Mutations Cause the Enzyme Deficiency and Porphyrin Accumulation

Table 1 Urinary porphyrin precursors and porphyrins in the affected proband and wild-type (WT) cats.

Precursor/porphyrin	WT (n = 8), µmol/mol Cr (range)^a	Wisconsin (r = 3)^b
Precursor/porphyrin	WT (n = 8), µmol/mol Cr (range)^a	µmol/mol Cr (range)	Fold change over WT	Percent of total I + III isomers
ALA	2,400 (980–4,300)	1100 (816–1,370)	0.46	NA^c
PBG	650 (200–2,200)	150 (60–210)	0.23	NA^c
URO I	0.40 (0.23–0.62)	1060 (480–1,480)	2,650	69.3
URO III	0.20 (0.10–0.35)	38 (20–58)	190	2.5
URO I/III ratio	2.0	28	14
COPRO I	1.7 (1.4–1.9)	416 (190–566)	245	27.2
COPRO III	0.72 (0.48–0.90)	15 (7–19)	20	1.0
COPRO I/III ratio	2.4	28	12

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