According to news reports, she died in her sleep, although the cause of death has not been determined. Her mother, Helen McCole Bartusiak, told CNN that Skye had been suffering from epileptic seizures in recent days.
"We think she had a seizure and choked and nobody was there," she said.
The actress's boyfriend found her in the garage apartment adjacent to her parents' home where she lived. Her mother started cardiopulmonary resuscitation on her daughter before paramedics arrived.
Bartusiak was only 7 years old when she won the role opposite Gibson in the hit movie about the Revolutionary War. She also appeared in The Cider House Rules (1999), with Charlize Theron and Tobey Maguire, and Don't Say A Word (2001), with Michael Douglas.
She also had parts on network shows like House, Lost, CSI and 24, where she had a recurring role at Megan Matheson.
In recent years, she has starred in short films, including a seven-minute comedy called Frame of Reference. She had been preparing to produce and direct her first feature film, her mother said.
A family friend told Deadline that she was a "brave and caring young woman" who "is deeply missed by her family and friends."
Funeral arrangements are pending.