NY- A transsexual who plowed through her trust fund, then attacked her 84-year-old mom in her Central Park West home was convicted yesterday of reckless assault.

“How can they do that?” the defendant, Diane Wells, 52, said after the verdict was read.

The weeklong trial pitted Wells against her younger brother, James Cheney, whom she said set her up.

Wells’ lawyer, Mel Sachs, said the mother, Constance Joyce Cheney, initially said she fell and broke her arm, only blaming Wells after a visit from her son, James.

“This case is about a selfish man – her son – who has manipulated his mother and used her as a pawn to satisfy his insatiable need for money,” Sachs told jurors.

But prosecutors said it was Wells who was the greedy child, attacking her mother when she refused to make Wells sole beneficiary of her estate.

“She was conflicted about coming to testify, but she did,” assistant district attorney Michael Kabakoff said of Cheney.

In harrowing testimony, the octogenarian described being punched in the head by Wells, then having her arm twisted until it broke in the May 2005 incident.

She said that when she asked Wells to help her to the bathroom, her daughter refused.

A home health aide discovered Cheney on a sofa in her $4 million apartment the next morning and called 911.

Wells faces up to one year behind bars when she is sentenced next month.

She declined to comment as she left the courthouse.