The 20-year-old actor had been receiving treatment for his condition, according to a spokesperson for his family.
A Boyce family spokesperson now tells ET that Boyce's seizure was a result of an ongoing condition that has been identified by his family as epilepsy.
At the time of his passing, the family revealed that he's been receiving treatment for "an ongoing medical condition."
An autopsy was performed on Monday, a spokeswoman for the Los Angeles County Medical Examiner-Coroner told ET, adding that the cause of death was deferred pending further investigation.
The young actor - best known for his work Disney Channel shows including Descendants, Shake It Up and Liv and Maddie - was mourned by his family, and many in the entertainment industry following news of his death.
Boyce's father, Victor, took to Twitter on Sunday to thank his son's fans for their outpouring of support and condolences following his family's tragic loss.
"I’m overwhelmed with the love and support our family has received," Boyce's devastated father wrote. "It really does help to ease the pain of this nightmare I can’t wake up from. I can’t thank you guys enough."
For more on the young star's life and legacy, and the tributes and memorials shared in recent days, watch the video below.
Cameron Boyce's 'Jessie' Co-Star Skai Jackson Tears Up Over His Death: 'He Was Like a Brother' (Exclusive)