I just discovered today that Mitt Romney is a direct descendant (great-great-grandson) of Parley P. Pratt, an associate of Joseph Smith and an influential early member of the Latter Day Saints.
Off-topic, but John Huntsman is also a direct descendant of Pratt (great-great-great grandson)...
(Mr. Pratt actually had 12 wives, 30 children, and 266 grandchildren)