CEP porphyria occurs rarely in animals and that is mostly in cattle. However it does appear in fox squirrels. According to a notation in the Merck medical book, all fox squirrels have this condition but it does not appear to affect them adversely,even though porphyrins are markedly increased. The pathogenesis of CEP lies with the uroporphyringen III cosynthase gene. Many different mutations of the human uroporphyrinogen III cosynthase gene have been identified.
Most patients have unrelated parents and have inherited a different mutation from each.
It is interesting in CEP that residual cosynthase activity persists even in the most severe cases. In CEP excess porphyrins accumulate in bone marrow mostly at the stage of erythroid cell maturation, when hemoglobin synthesis is most active. The symptomology of CEP includes skin blistering which is usually severe, and begins soon after birth. The skin blistering is usually accompanied by anemia and red urine. Some cases are relatively mild with onset of symptoms in adult life.