The two law firms representing Sam Altman’s sister in her sexual abuse lawsuit against the OpenAI chief executive said Monday they are withdrawing from her case.

In filings in St. Louis federal court, the Mahoney Law Firm and the Simon Law Firm cited “an unfortunate general breakdown in the attorney-client relationship” between them and Annie Altman, and said continuing to represent her in the civil lawsuit was “impracticable.”

The law firms also cited professional considerations, and circumstances of a privileged and confidential nature, and said Annie Altman is seeking new counsel. Court approval is required for the withdrawal.

Sam Altman has denied his sister’s accusations that he sexually abused and raped her at various times between 1997 and 2006 at the family home in suburban Clayton, Mo., starting when she was three and he was 12.

Lawyers for Sam Altman did not immediately respond to requests for comment. Contact information for Annie Altman was not immediately available.

The Altman family has said Annie Altman has mental health challenges and received financial support from them.

Sam Altman, now 41, said she began accusing him on social media of sexual abuse after they rejected her extortionate demand for more money.

He is countersuing his sister for defamation over her posts, including a video that said “an almost tech billionaire” molested her, and seeking $1 in damages.

The case is separate from Elon Musk’s civil lawsuit accusing OpenAI and Altman of betraying OpenAI’s original mission to benefit humanity as a nonprofit.

Jury selection in that case began on Monday in the Oakland, Calif., federal court.

Sam Altman became a face of the artificial intelligence boom after the chatbot ChatGPT was released in 2022. He is worth $3.5 billion according to Forbes magazine.