I have seen this lovely brindle pattern like that on DS's too, but mosty without the lighter belly, neck and leg coloring that occurs in your girl and the picture of the Akita that Marjolein posted. I agree that your Izzy is a bit stockier and longer in the back than you would expect to see in a DS, as far as I can tell without a full side shot though.
The most poignant difference between Izzy and a DS would be the lack of mask, though. DS's almost always have a mask. Sometimes it is minimal, but you would still see black lines around the lips at least. I do not see any mask on Izzy (and it brings out her lovely brindling on her face, so I think that mother nature knew what she was doing when adorning Izzy like this)
and the gene that is responsible for the mask is dominant. If at least one parent had been a DS, how could she miss out on something that 99% of DS's have?
Unrelated: Thank you for adopting a shelter dog and working past some issues.
You helped save a life and I hope that your reward lies in a wonderful relationship with a lovely dog.
about the tiger fur.
Googling akita brindle mixes led to some photos that I could see some of Izzie in. 
Judith Van Neerland Dutch Shepherds 
) So there is no profile to link to a DS, so even if you're dog has DS in it, unlike labrador or something, they simply will not be able to locate it :dswink" Total waste of money, spend it on some good dogtoys :dswink" 
Facebook page.
