According to the AKC (American Kennel Club), the Blue color is not included in the Boston Terrier breed standard. Blue Boston Terriers don’t qualify for the dog shows.
There is a lot of people who are against the breeding of colored Boston Terriers. However, a blue Boston Terrier is a great companion dog and generally has a life span of 11 to 15 years. Blue Boston Terriers can live an healthy life as well as the standard Boston Terriers.
No known medical problems are specifically related to the blue Boston Terriers. Like Boston Terriers in general, they have sensitive digestive systems and they can get some health issues, including cataracts, cherry eye, allergies, deafness, and luxating patellas.
Blue is a dilute of black. This dilution is due to a mutation of the dilution gene which is the Chromosome 25 in canines. So instead of being black the coat appears to have a gray appearance.