In other species: domestic cat , pig , indicine cattle (zebu)

Categories: Integument (skin) phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 263700 (trait)

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal recessive

Disease-related: yes

Key variant known: no

Cross-species summary: Porphyrins are a class of organic compounds characterised by four pyrrole nuclei connected in a ring structure. When combined with iron, porphyrins form haem, which is a component of haemoglobin, cytochromes, catalases and peroxidases. Thus, porphyrins are constituents of many compounds that play a vital role in biological systems. The biosynthesis of porphyrins involves a six-step process, starting with aminolaevulinic acid (ALA) and ending with protoporphyrin. Each step is catalysed by an enzyme. A deficiency of any one of these enzymes results in a buildup of intermediates prior to the step for which the enzyme is lacking, and a deficiency of intermediates after that step. In much of the literature, these intermediates are loosely called porphyrins. Congenital eryhtropoietic porphyria results from a deficiency of the third enzyme, uroporphyrinogen III cosynthetase, and a consequent buildup of intermediates (i.e. a buildup of porphyrins) that have been synthesised in the three previous steps.

Species-specific name: Pink tooth

Molecular basis: Agerholm et al. (2012) sequenced the candidate gene UROS in affected and non-affected cattle, and identified a SNP in intron 8 that segregates with the disorder in all available cases. However, the authors concluded that analysis of more cases is required before a definite conclusion can be drawn about the causative mutation.