There are several tiny splinter groups, each headed by a self-appointed "prophet", but more properly called a "dirty old man", which claim to be following the Book of Mormon as the word of God. Their total numbers are probably only a few hundred, or maybe a few thousand tops. They live out in the boonies, have little money beyond what they scrape up through welfare fraud, and have a habit of forcibly "marrying" their adolescent nieces, each others daughters, etc., and living in polygamous families. Like all wacko splinter groups, they claim to be the "real" Mormons or whatever they're a splinter of. David Koresh's "Branch Davidian" group was a splinter version of the Seventh-Day Adventist Church, and also claimed to be the "real" church, while Koresh kept his followers isolated from the rest of society and helped himself to sex with their little girls.
I don't know about you, but I'm a lot more inclined to take J.W. Marriott's (Mormon and Chairman/CEO of the Marriott Corp.) and Senator Orrin Hatch's word for which church is the "real" Mormon Church. Maybe you prefer to take the dirty old men's word. It's a free country -- you get to choose.