Worse immunity in blue merles?

[DieDany]

In the last time I heard some opinions that the merle gene is responsible for significantly worse immunity (not only in Shelties). Some people say that there are more vision/hearing issues and intolerance for some drugs but as far as I know it's the CEA/PRA thing and the MDR gene that are responsible for some issues and they are not related to any specific color. But as far as the immunity I don't really know What do you think about this statement?

[ClantyreSheltie]

Originally Posted by DieDany

In the last time I heard some opinions that the merle gene is responsible for significantly worse immunity (not only in Shelties). Some people say that there are more vision/hearing issues and intolerance for some drugs but as far as I know it's the CEA/PRA thing and the MDR gene that are responsible for some issues and they are not related to any specific color. But as far as the immunity I don't really know What do you think about this statement?

I think there is a *very* small grain of truth. Of course it has nothing to do with drug intolerance. The hearing/sight thing has to do with the dilution of the pigment. For the same reason a lot of Dalmations suffer some form of deafness, a heavily diluted sheltie could potentially suffer deafness. Merle is basically dilution, then you add the white factoring, and the Piebald we see in some dogs (which is also what causes Dalmations to be white), and it's entirely possible that we have more unilaterally deaf merles than we know about.

As to immunity, I would tend to stay away from poorly pigmented dogs in general, regardless of base color. I do think the poorly pigmented dogs have other issues, though I have no rational basis for thinking that.

[labgirl]

Merlin is a blue merle and comes from good lines. When he caught Seasonal Canine Illness, which can be a killer and, as yet has no vaccine, his friend who is a cross breed and the same age caught it at the same time. Merlin was poorly but recovered quickly, his friend nearly died and was in the vets on ABs and a drip.

Does that imply he had a stronger immune system than the cross breed? I don't know.

Sometimes I think these things are all relative, yes some pigment colorations can cause faults, as mentioned above deafness. But it does not mean a dog's immune system or future health is/will be poor.