Tendencies (Breed, Size, Color):

Breed:
More purebred dogs, than mix
In the ME community we see large numbers of breeds
See more in German Shepherds
We have seen Bulldog, Chinese Crested, Doxie, Great Dane, Lab, etc (can go to the website https://www.rehomingmegaesophagusdogs.com and see the Needs, On Radar, and Success Stories pages)
Most commonly affected are GSDs, Labs and Golden Retrievers, Great Danes, Mastiffs, Boxers, Pugs, Doxies, Greyhounds, Poodles, Shelties and a fair number of the bully breeds

Size:
Don’t think that we can say it’s more/less common in large or small breeds

Gender:
No breed specificity
Seeing a lot more in puppies

Rules of thumb:
Don’t breed a dog who has offspring with ME
If puppy(ies) diagnosed verify first whether just ME or ME caused by PRAA (PRAA isn’t hereditary as far as we know but ME can be)
There are researchers doing DNA testing for breed to ME
If puppy(ies) have med, parents must be evaluated with potential to alter both so not passed forward
All offspring of ME puppies must also be altered to keep ME from being passed forward
Responsible breeders are those who care enough to learn about this condition and do the best they can to avoid it in their lines of dogs

Research:
Dr Leigh Ann  Clark at Clemson University is studying breed specific DNA to ME
Researchers at the University of Pennsylvania School of Medicine, in Philadelphia, have discovered stem cells in the esophagus of mice that are able to grow into tissue-like structures and form parts of an esophagus lining when placed into immune-deficient mice.1

Helpful websites:
https://www.rehomingmegaesophagusdogs.com/
http://www.hsus.org/pets/pet_care/trouble_affording_your_pet.html
https://www.justanswer.com/dog-health/37mbv-genetic-predisposition-megaesophagus-canines.html
https://clemsoncaninegenetics.webs.com/megaesophagus.htm