
Testing of cats: CEP
Related tests
- Combination House Cat and European Cat 1 CEP + Gangliosidosis (AB variant) + GM2 + HCM + Haemophilia B + Blood Group DNA test + PK deficiency
Congenital erythropoietic porphyria (CEP)
Congenital erythropoietic porphyria is a very rare inherited disease that occurs in cats, cattle, pigs, sheep and humans. It is manifested by erythrodontia, i.e. brown teeth that fluoresce pink under UV light, and reddish-brown urine.
Porphyrins are organic compounds that combine with iron to form heme. Heme is a component of many compounds (including haemoglobin, the oxygen-carrying molecule in the blood) that play essential roles in biological systems. The synthesis of heme is a complex multi-step process catalysed by a number of enzymes. Due to the deficiency of the enzyme uroporphyrinogen III synthase, intermediate porphyrins accumulate in teeth, bones, and skin and are excreted in urine and feces. Some animals develop severe sensitivity to the sun (called photosensitivity) and haemolytic anaemia due to a lack of circulating red blood cells.
In cats, the disease is caused by the synergistic interaction of two missense mutations c.[140C>T;331G>A] in the UROS gene, which encodes the enzyme uroporphyrinogen III synthase.
The mode of inheritance of the mutation is autosomal recessive. This means that only individuals who inherit the mutated gene from both parents will develop the disease. Carriers of the mutated gene are clinically healthy but pass the mutation on to their offspring. In the case of a mating between two heterozygous individuals, theoretically 25% of the offspring will be completely healthy, 50% of the offspring will be carriers and 25% of the offspring will inherit the mutated gene from both parents and will therefore be affected by the disease.
The genetic test can clearly reveal the genotype of the animal and is a useful tool for breeders to prevent unintentional breeding of affected kittens.
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References:
Clavero, S., Bishop, DF., Giger, U., Haskins, ME., Desnick, RJ. : Feline congenital erythropoietic porphyria: Two homozygous UROS missense mutations cause the enzyme deficiency and porphyrin accumulation. Mol Med 16:381-388, 2010. Pubmed reference: 20485863