Alexis Arquette died from a heart attack and battled HIV for 29 years, according to her death certificate.
The transgender character actress and sibling of actors David, Rosanna, Richmond and Patricia Arquette died on September 11 in Los Angeles. She was 47.
The death certificate released on Tuesday lists cardiac arrest as her immediate cause of death and that Alexis suffered a bacterial infection three weeks before her death, Associated Press reports.
HIV is also noted as an underlying cause of death.
Alexis memorably played a trans sex worker in Last Exit To Brooklyn and a Boy George impersonator in The Wedding Singer.
In a statement, the Arquettes said that their sister's career "was cut short, not by her passing, but by her decision to live her truth and her life as a transgender woman".