The maltese dilution (also known as the maltese mutation or blue dilution) is a color variety that mostly occurs in members of Felidae, commonly affecting house cats. The "Russian blue" breed is the most famous example of that color variety.

"The Dense pigment gene, D/d, codes for melanophilin (MLPH), a protein involved in the transportation and deposition of pigment into a growing hair. When a cat has two of the recessive d alleles (Maltese dilution), black fur becomes "blue" (appearing gray), chocolate fur becomes "lilac" (appearing light brown), cinnamon fur becomes fawn, and red fur becomes cream."
-- https://en.wikipedia.org/wiki/Cat_coat_genetics#Dilution_and_Maltesing




You might say that a domestic cat-specific mutation has nothing to do with lions... when in reality it affects a broad spectre of species, although is much more rare. A great example would be the elusive blue bob cats that haven't been seen for over a century, until a hunter shot one in 2016. It is also believed that cheetahs carry the Maltese dilution gene, although I could not find any sources confirming this infromation, thus making it unreliable.

Dead animal ahead! No blood or gore, just an image of the maltese bobcat that was shot in 2016.




There were multiple accounts of Blue Tiger sightnings in Asia, but none of them were confirmed, thus making the tigers with such mutation nothing more than an urban legend (that can be proven real). This might be a turn-off from the idea, however both melanistic lions and tigers are missing scientifically verified accounts, as well as many mutations in Lioden do not occur in big cats (or are made-up, like Primals).
This is not a real photo, but an artist's vision of what a Maltese tiger will look like.




How do we implement it?
Maltese dilution can be implemented the same way as leucism and erythrism - by adding a blue layer over the coloration of the lion, thus giving it a blue tint.
Here is a half-assed example that I created using my main male Baikal -
Normal Baikal

Baikal with maltese mutation (he came out way too blue, but I guess that will do as an example)




Reasons To Vote For
-Leucism and Erythrism are confirmed mutations that might be implemented in a similar way to the Maltese dilution.
-Mutation variation is great, hell yeah!

Reasons to Vote Against
-Lioden already has maltese-colored markings and bases, for example Elysian.
-It is not proven whether the maltese mutation can occur in big cats.