Yes, Michael Jackson was born black, but lost his skin pigmentation due to vitiligo a common skin condition that makes the skin lose its natural color. Since Michael was on the public eye, he couldn't go out in public with two different skin colors, so he underwent bleaching for the other parts of his body. There is really no reliable standard cure for vitiligo.
"Vitiligo is a chronic relatively common dermatologic disorder that causes depigmentation in patches of skin. It occurs when the melanocytes, the cells responsible for skin pigmentation, die or are unable to function. The precise pathogenesis, or cause, of vitiligo is complex and not yet fully understood. There is some evidence suggesting it is caused by a combination of autoimmune, genetic, and environmental factors. The population incidence worldwide is considered to be between 1% and 2%"
|Includes CC-BY-SA content from Wikipedia's Vitiligo article (authors)|