Iris pigmentation trait known as "tiger eye" (amber-golden iris) described in the Puerto Rican Paso Fino, associated with two variants of the SLC24A5 gene. It is not a disease: in homozygosity or as a compound heterozygote (Tiger-eye 1/Tiger-eye 2) no ocular abnormalities or changes in coat colour have been observed. It is a phenotypic marker of interest to breeders.

Documented breed: Puerto Rican Paso Fino (PRPF). Frequencies: limited data.

- Amber or golden iris ("tiger eye")\n- No associated ocular abnormalities in the available studies\n- No changes in coat colour\n- Does not imply disease

Mack et al. (2017) analysed the iris of Puerto Rican Paso Fino horses and associated two SLC24A5 variants (Tiger-eye 1 and Tiger-eye 2) with tiger-eye pigmentation. None of the 122 brown-eyed horses was homozygous for the associated alleles or a compound heterozygote, and no variant appeared in 196 horses from four related breeds without the phenotype (PMID 28655738).

- It is a pigmentation trait, not a disease: it does not require removing breeding animals\n- Use the genotype as phenotypic information for the breeder\n- Do not interpret it as a risk of ocular pathology

Phenotypic trait (amber-golden iris) of the Puerto Rican Paso Fino; in homozygosity or compound heterozygote (Tiger-eye 1/Tiger-eye 2) no ocular abnormalities have been described. Non-pathological trait of interest to breeders.

1. Mack M, Kowalski E, Grahn R, et al. Two variants in SLC24A5 are associated with tiger eye, a novel iris color phenotype in the Paso Fino horse. Anim Genet. 2017. PMID 28655738. 2. OMIA:002124-9796 (Coat colour, albinism, oculocutaneous type VI, horse).