I am not real sure if it is hereditary or not. But if there is an open fontanel, especially a large one, you would also want to have it checked out for hydrocephalus or water on the brain. Sometimes it can go hand in hand but not always.
Some pups are born with no open fontanel. Some are born with a small one that closes within a week. Sometimes it closes in months sometimes up to a year and some never close. Some will still live a normal lifespan, some have other problems and don't. |