I'm not sure what your civil cause of action would be. On your facts there might be a percentage of time your mother provided support sufficient to claim you for tax purposes.
On a non-legal note - suing one's own mother raises all kinds of negative Karma issues.
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If she was entitled to claim you as a dependent on her taxes, then the money is hers. It's not something she "takes you off of." She may be able to declare you as a dependent even if you are not living in her home, depending on whether or not you are in school and if she is paying your expenses.
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You can sue your mother. You can sue Santa Claus. But you have no basis for winning. What she gets from the IRS is not money that would otherwise go to you. If she shouldn't claim you, then you should report her to the IRS Fraud Unit. But that doesn't say much about your family.