The star from Atlanta, Georgia, rose to fame more than a decade ago with his career closely tied to that of Grammy-winner Young Thug, as the pair were members of the group Rich Gang.
Quan - real name Dequantes Devontay Lamar - had other hits including the trap single Type of Way in 2013 and Flex (Ooh, Ooh, Ooh) - which inspired a track from rapper iLoveMemphis titled Hit The Quan in 2016.
The viral song sparked a "Hit The Quan" dance craze, after the rapper popularised a series of low-stepping, arm-swinging dance movements in the music video for Flex (Ooh, Ooh, Ooh).
Kendrick Lamar, who has won 17 Grammy Awards, incorporated the dance move into a music video for his track These Walls - which featured a cameo from Brooklyn Nine-Nine actor Terry Crews.
Quan's death was confirmed by the Fulton County Medical Examiner's Office, which did not provide a cause.
"On Thursday, September 5, 2024, the Fulton County Medical Examiner was notified by Grady Memorial Hospital of the death of Dequantes Devontay Lamar," a spokesperson told the PA news agency.
An autopsy was scheduled for Friday.
Titans from the music industry weighed in on social media to express their sorrow at his death.
Megan Thee Stallion wrote: "RIP to one of the best," alongside a broken-heart emoji as she added a photograph of Quan to her Instagram story.
Fellow Atlanta-based rapper Quavo said: "May God be with US, never saw this being a part of our journey."
He shared a photograph of the pair to his Instagram story, which also featured his late nephew and fellow Migos group member Takeoff.
The late rapper was shot and killed in 2022.
Similarly, the star was remembered during the R&B Hip-Hop Power Players awards in Los Angeles.
After being named artist of the year, US rapper Playboi Carti said: "RIP Rich Homie Quan", before exiting the stage with his award.
US star 2 Chainz also remembered the rapper on Instagram, telling his 12.7 million followers: "Dam lil brother, we just spoke about shooting a video, special prayer for you and your family, and pray for any and everybody that's dealing with something."
A representative for Quan has been contacted for comment.
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