The sister of billionaire OpenAI Chief Executive Sam Altman filed a lawsuit accusing him of sexually abusing her regularly between 1997 and 2006, prompting him and other family members to deny her claims.

In a complaint filed on Monday in St. Louis federal court, Ann Altman said the abuse occurred at the family home in suburban Clayton, Missouri, beginning when she was three and her brother was 12.

Now 30, Ann Altman said the abuse included “numerous acts” of rape, sexual assault, molestation, sodomy and battery until she was 11 or 12 years old.

She is seeking at least $75,000 of damages, plus punitive damages, for alleged injuries including post-traumatic stress disorder, severe emotional distress, mental anguish and depression.

“All of these claims are utterly untrue,” Sam Altman, 39, said in a post on Tuesday with his mother and two brothers on X.They also called it “incredibly difficult” to care for Ann Altman, known as Annie, who they said refuses conventional treatment for mental health challenges.

“Our family loves Annie and is very concerned about her well-being,” they said. “Annie receives monthly financial support, which we expect to continue for the rest of her life. Despite this, Annie continues to demand more money from us.”

Lawyers for Ann Altman did not immediately respond to requests for comment on Wednesday about the statement and the lawsuit.

Sam Altman co-founded OpenAI alongside Elon Musk and others, and became one of the technology world’s biggest names after the 2022 launch of the artificial intelligence tool ChatGPT.

Backed by Microsoft (MSFT.O) OpenAI was valued at $157 billion in October after raising $6.6 billion from investors.

Sam Altman is worth about $1.1 billion, according to Forbes magazine.