A frameshift mutation in the LYST gene is responsible for the Aleutian color and the associated Chédiak-Higashi syndrome in American mink.

One of the colors of mink is Aleutian (aa)-a specific gun-metal gray pigmentation of the fur-commonly used in combination with other color loci to generate popular colors such as Violet (aammpp) and Sapphire (aapp). The Aleutian color allele is a manifestation of mink Chédiak-Higashi syndrome (CHS), which has been described in humans and several other species. As with forms of CHS in other species, we report that the mink CHS is linked to the lysosomal trafficking regulator ( LYST ) gene. Furthermore, we have identified a base deletion (c.9468delC) in exon 40 of LYST, which causes a frameshift and virtually terminates the LYST product prematurely (p.Leu3156Phefs*37). We investigated the blood parameters of three wild-type mink and three CHS mink. No difference in the platelet number between the two groups was observed, but an accumulation of platelets between the groups appears different when collagen is used as a coagulant. Microscopic analysis of peripheral blood indicates giant inclusions in the neutrophils of the Aleutian mink types. Molecular findings at the LYST locus enable the development of genetic tests for analyzing the color selection in American mink.