In other species: dog , domestic cat , Arabian camel , taurine cattle , goat , water buffalo

Categories: Pigmentation phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 172800 (trait) , 164920 (gene)

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal dominant + recessive lethal

Disease-related: no

Key variant known: yes

Year key variant first reported: 2015

Cross-species summary: Variable degree of white spotting ranging from tiny white spots up to completely white animals. The absence of pigment is caused by the absence of skin melanocytes ("leucism, leucistic"), not by failure in the biochemical reactions required for pigment synthesis.

Molecular basis: Haase et al. (2015): c.1978+2T>A in a splice donor site Fenn et al. (2017) confirmed the likely causality of the above mutation, concluding "the results of this study enhance the evidence that the previously identified variant is associated with white spotting in donkeys. Because the splice site variant was not observed in the homozygous state, this result also supports the hypothesis that homozygosity for this genetic variant is incompatible with life. The presence of the variant in donkeys of different breeds (Miniature Donkey and Mammoth Jack) suggests that the variant probably arose prior to breed separation" Tanaka et al. (2020) provided evidence to reinforce the conclusion that "white spotting in donkeys . . . [is] less variable than in horses [being due to heterozygosity for just one variant, namely c.1978+2T>A] and support homozygosity being lethal, highlighting the caution that should be taken when mating spotted donkeys to avoid producing non‐viable foals".

Associated gene: