The autopsy proved that he had vitiligo.I don't subscribe to the idea that he has vitiligo at all.
Michael Jackson’s Autopsy Revealed Numerous Surgical Scars; Confirmed Vitiligo
Michael Jackson had always insisted that he suffered from vitiligo, a skin condition which causes patches of lost pigmentation. But it wasn’t until after his death that an autopsy confirmed the truth behind his unusual skin color
He changed it because he hated his dad Joe, not to be White.He also changed his whole face to mimic white features. And his kids aren't even biologically his. I think he has severe racial identity issues.
He said "I'm a black American, I am proud of my race. I am proud of who I am. I have a lot of pride and dignity." - Michael Jackson
Michael Jackson was staunchly pro-Black and never once ran away from it.