The "J" in "Michael J. Fox doesn't stand for anything. His birth name is "Michael Andrew Fox," but when he registered for the Screen Actor's Guild, the name "Michael Fox" was already taken, so he added the J for two reasons: 1) He didn't want to be "Michael A. Fox" because it presented a play on words, 2) He was paying homage to actor Michael J. Pollard.
Parkinson's disease
Mike Pyeatt's birth name is Michael J. Pyeatt.
Megan Jamie Vivica A. Michael J. Red
Michael J. Wytrwal was born in 1882.
He has Parkinson's disease, but other than that he is fine as far as I know.
Michael J Berwick's birth name is Michael John Berwick.
Michael J. Fox used a J as his middle initial because when he registered for the Screen Actor's Guild, the name "Michael Fox" was already taken. His middle name is Andrew, but he didn't want to be known as "Michael A. Fox" (it presented a play on words), so he added the J as a homage to actor Michael J. Pollard.
Michael Livesey's birth name is Michael J. Livesey.
Michael Rodrick's birth name is Michael J. Rodrick.
Michael Koenen's birth name is Michael J. Koenen.
Michael Diehl's birth name is Michael J. Diehl.
Michael Arthofer's birth name is Michael J. Arthofer.
Michael Bronte's birth name is Michael J. Bryant.
Michael Oczko's birth name is Michael J. Oczko.
Michael Nicely's birth name is Michael J. Nicely.
Michael Faella's birth name is Michael J. Faella III.