Margaret Wilkinson was the foster mother of Tinya Wazzo
Not much is known about Margaret Wilkinson's past, other than the fact she apparently took at least three foster children under her care, and all of them were admitted to hospitals with severe injuries, yet somehow managed to escape justice.
Eventually, she took under her care a young amnesiac girl named Tina. She frequently berated and beat her up, and when her powers started to manifest, she kicked her out of her house, believing she was a mutant (unaware that she was actually an alien).
Some months later, she apparently was contacted by Graydon Creed of the Friends of Humanity, and struck a deal with them: under the guise of regaining the custody of her foster daughter (by claiming that the Xavier Institute had taken her illegally) she would later turn her over to them, and she'll get a payoff for it. The plan was discovered and exposed by the Justice League and the X-Men. She went into a fit of rage and tried to slap Tinya when she confronted her. In doing so, she added one more charge of assault against her, thus assuring that she would never be able to take any other foster child under her care.