New details have emerged on Karen Houghton's final moments. 

Kris Jenner's younger sister died unexpectedly on March 18 at the age of 65, and now her cause of death has been revealed.

Karen died due to heart issues, with her cause of death listed as cardiac arrest and sudden cardiac arrhythmia, according to her death certificated obtained by TMZ on April 12.

The document listed Type 2 diabetes as a secondary, underlying cause and additionally noted that the former flight attendant had bipolar disorder. Karen—the youngest daughter of Mary Jo "M. J." Shannon and Robert Houghton—was cremated following her passing.

Last month, Kris mourned the loss of her sister in a poignant social media tribute.

"Karen was beautiful inside and out," the 68-year-old wrote on X March 19. "She was the sweetest, kindest, the most sensitive and vulnerable and so so funny. She always felt grateful and thankful for her life and treasured her family and friends and especially her beautiful daughter."

Although the sisters had at one point been estranged, they appeared to be on better terms before Karen's passing, with Kris also writing, "She holds such a huge part of my heart and I cherish every single memory we have together."

Karen's daughter Natalie Zettel—her only child with ex-husband Mark Zettel—shared her own moving words about her mother, saying that she couldn't believe her mom was gone.

"You were my best friend, my everything," the 26-year-old wrote on Instagram March 20. "The best mother a daughter could ever ask for and I'm so grateful to have had a mother like you."

For more of Kris and Karen's life together, keep reading.

Clad in all-white, Kris Jenner posed with her late sister Karen Houghton, who passed away in March 2024 at the age of 65. 

Kris, her mom Mary Jo Campbell and her sister Karen smiled for a photo in front of the Christmans tree while wearing stunning suitwear.  

Kris and Karen soaked up some sun in this throwback photo.

Karen and Mary Jo posed with a young Kourtney Kardashian around the kitchen table. 

Mary Jo and her youngest daughter, Karen, matched in crisp all-white outfits. 

In this adorable throwback, Karen wrapped her arms around her daughter Natalie Zettel while she flashes a wide grin, festive in a holiday sweater.