The Brown family in the Jules Verne Train.
The Brown family consisted of Doctor Emmett L. Brown, his wife Clara, and their two sons Jules and Verne named for Jules Verne.
They were all involved in Doc's travels through time on their time traveling train.
Doc's ancestors were the Von Brauns, who emigrated from Germany in 1908 and anglicized their surname to Brown after America's entry into the First World War. However, little is known about Doc's father, save for that Emmett's father was a judge who had to take some time to accept Emmett's interest in science. The only thing known about Doc's mother is that her maiden name was Lathrop, which became Emmet's middle name.
Doc would spend his summers as a young boy with his Uncle Otto Von Braun.
There is no evidence that Emmett Brown had any siblings, and he apparently was the sole heir of the family fortune, which was sufficient enough for him to develop a time machine.
The family owned the Brown mansion which burned down in 1962.
In the Video Game, Doc is told by one version of Marty from the future that he will have great-grandchildren, and that they were in some as yet unexplained peril.
Family Tree
Mr. Von Braun + Mrs. Von Braun Clayton family | | +---------------------+ +------------------------------------+ Oliver Brown Judge Erhardt Brown + Sarah Lathrop Daniel Clayton + Martha Clayton Ulysses S. Clayton | | Emmett Brown--------+--------Clara Clayton Brown | +--------------------------+ | | Jules Brown Verne Brown